public abstract class

Dialect

extends Object
java.lang.Object
   ↳ org.hibernate.dialect.Dialect
Known Direct Subclasses
Known Indirect Subclasses

Class Overview

Represents a dialect of SQL implemented by a particular RDBMS. Subclasses implement Hibernate compatibility with different systems.

Subclasses should provide a public default constructor that register() a set of type mappings and default Hibernate properties.

Subclasses should be immutable.

Summary

Constants
String CLOSED_QUOTE
String DEFAULT_BATCH_SIZE
String NO_BATCH
String QUOTE Characters used for quoting SQL identifiers
Protected Constructors
Dialect()
Public Methods
String appendIdentitySelectToInsert(String insertString)
Provided we supportsInsertSelectIdentity(), then attach the "select identity" clause to the insert statement.
String appendLockHint(LockMode mode, String tableName)
Some dialects support an alternative means to SELECT FOR UPDATE, whereby a "lock hint" is appends to the table name in the from clause.
String applyLocksToSql(String sql, LockOptions aliasedLockOptions, Map keyColumnNames)
Modifies the given SQL by applying the appropriate updates for the specified lock modes and key columns.
boolean areStringComparisonsCaseInsensitive()
Are string comparisons implicitly case insensitive.
boolean bindLimitParametersFirst()
Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?
boolean bindLimitParametersInReverseOrder()
ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit.
SQLExceptionConverter buildSQLExceptionConverter()
Build an instance of the SQLExceptionConverter preferred by this dialect for converting SQLExceptions into Hibernate's JDBCException hierarchy.
char closeQuote()
The character specific to this dialect used to close a quoted identifier.
int convertToFirstRowValue(int zeroBasedFirstResult)
Hibernate APIs explicitly state that setFirstResult() should be a zero-based offset.
CaseFragment createCaseFragment()
Create a CaseFragment strategy responsible for handling this dialect's variations in how CASE statements are handled.
JoinFragment createOuterJoinFragment()
Create a JoinFragment strategy responsible for handling this dialect's variations in how joins are handled.
boolean doesReadCommittedCauseWritersToBlockReaders()
For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?
boolean doesRepeatableReadCauseReadersToBlockWriters()
For the underlying database, is REPEATABLE_READ isolation implemented by forcing writers to wait for read locks to be released?
boolean dropConstraints()
Do we need to drop constraints before dropping tables in this dialect?
boolean dropTemporaryTableAfterUse()
Do we need to drop the temporary table after use?
boolean forUpdateOfColumns()
Is FOR UPDATE OF syntax supported?
boolean forceLimitUsage()
Generally, if there is no limit applied to a Hibernate query we do not apply any limits to the SQL query.
String generateTemporaryTableName(String baseTableName)
Generate a temporary table name given the base table.
String getAddColumnString()
The syntax used to add a column to a table (optional).
String getAddForeignKeyConstraintString(String constraintName, String[] foreignKey, String referencedTable, String[] primaryKey, boolean referencesPrimaryKey)
The syntax used to add a foreign key constraint to a table.
String getAddPrimaryKeyConstraintString(String constraintName)
The syntax used to add a primary key constraint to a table.
String getCascadeConstraintsString()
Completely optional cascading drop clause
String getCastTypeName(int code)
Get the name of the database type appropriate for casting operations (via the CAST() SQL function) for the given java.sql.Types typecode.
String getColumnComment(String comment)
String getCreateMultisetTableString()
Slight variation on getCreateTableString().
String[] getCreateSequenceStrings(String sequenceName)
This method is deprecated. Use getCreateSequenceString(String, int, int) instead
String[] getCreateSequenceStrings(String sequenceName, int initialValue, int incrementSize)
An optional multi-line form for databases which supportsPooledSequences().
String getCreateTableString()
Command used to create a table.
String getCreateTemporaryTablePostfix()
Get any fragments needing to be postfixed to the command for temporary table creation.
String getCreateTemporaryTableString()
Command used to create a temporary table.
String getCrossJoinSeparator()
Get the separator to use for defining cross joins when translating HQL queries.
String getCurrentTimestampSQLFunctionName()
The name of the database-specific SQL function for retrieving the current timestamp.
String getCurrentTimestampSelectString()
Retrieve the command used to retrieve the current timestamp from the database.
final Properties getDefaultProperties()
Retrieve a set of default Hibernate properties for this database.
static Dialect getDialect()
Get an instance of the dialect specified by the current System properties.
static Dialect getDialect(Properties props)
Get an instance of the dialect specified by the given properties or by the current System properties.
String getDropForeignKeyString()
String[] getDropSequenceStrings(String sequenceName)
The multiline script used to drop a sequence.
String getDropTemporaryTableString()
Command used to drop a temporary table.
String getForUpdateNowaitString()
Retrieves the FOR UPDATE NOWAIT syntax specific to this dialect.
String getForUpdateNowaitString(String aliases)
Get the FOR UPDATE OF column_list NOWAIT fragment appropriate for this dialect given the aliases of the columns to be write locked.
String getForUpdateString()
Get the string to append to SELECT statements to acquire locks for this dialect.
String getForUpdateString(String aliases)
Get the FOR UPDATE OF column_list fragment appropriate for this dialect given the aliases of the columns to be write locked.
String getForUpdateString(LockOptions lockOptions)
Given LockOptions (lockMode, timeout), determine the appropriate for update fragment to use.
String getForUpdateString(String aliases, LockOptions lockOptions)
Get the FOR UPDATE OF column_list fragment appropriate for this dialect given the aliases of the columns to be write locked.
String getForUpdateString(LockMode lockMode)
Given a lock mode, determine the appropriate for update fragment to use.
final Map<StringSQLFunction> getFunctions()
Retrieves a map of the dialect's registered functions (functionName => SQLFunction).
String getHibernateTypeName(int code, int length, int precision, int scale)
Get the name of the Hibernate Type associated with the given java.sql.Types typecode with the given storage specification parameters.
String getHibernateTypeName(int code)
Get the name of the Hibernate Type associated with the given java.sql.Types typecode.
String getIdentityColumnString(int type)
The syntax used during DDL to define a column as being an IDENTITY of a particular type.
String getIdentityInsertString()
The keyword used to insert a generated value into an identity column (or null).
String getIdentitySelectString(String table, String column, int type)
Get the select command to use to retrieve the last generated IDENTITY value for a particular table
Set<String> getKeywords()
String getLimitString(String query, int offset, int limit)
Given a limit and an offset, apply the limit clause to the query.
LockingStrategy getLockingStrategy(Lockable lockable, LockMode lockMode)
Get a strategy instance which knows how to acquire a database-level lock of the specified mode for this dialect.
String getLowercaseFunction()
The name of the SQL function that transforms a string to lowercase
int getMaxAliasLength()
What is the maximum length Hibernate can use for generated aliases?
Class getNativeIdentifierGeneratorClass()
The class (which implements IdentifierGenerator) which acts as this dialects native generation strategy.
String getNoColumnsInsertString()
The fragment used to insert a row without specifying any column values.
String getNullColumnString()
The keyword used to specify a nullable column.
String getQuerySequencesString()
Get the select command used retrieve the names of all sequences.
String getReadLockString(int timeout)
Get the string to append to SELECT statements to acquire WRITE locks for this dialect.
ResultSet getResultSet(CallableStatement statement)
Given a callable statement previously processed by registerResultSetOutParameter(CallableStatement, int), extract the ResultSet from the OUT parameter.
String getSelectClauseNullString(int sqlType)
Given a java.sql.Types type code, determine an appropriate null value to use in a select clause.
String getSelectGUIDString()
Get the command used to select a GUID from the underlying database.
String getSelectSequenceNextValString(String sequenceName)
Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement.
String getSequenceNextValString(String sequenceName)
Generate the appropriate select statement to to retrieve the next value of a sequence.
String getTableComment(String comment)
String getTableTypeString()
String getTypeName(int code)
Get the name of the database type associated with the given java.sql.Types typecode.
String getTypeName(int code, int length, int precision, int scale)
Get the name of the database type associated with the given java.sql.Types typecode with the given storage specification parameters.
final List<BasicType> getTypeOverrides()
Retrieve dialect-specific types for overriding "basic" types.
ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter()
String getWriteLockString(int timeout)
Get the string to append to SELECT statements to acquire WRITE locks for this dialect.
boolean hasAlterTable()
Does this dialect support the ALTER TABLE syntax?
boolean hasDataTypeInIdentityColumn()
Whether this dialect have an Identity clause added to the data type or a completely separate identity data type
boolean hasSelfReferentialForeignKeyBug()
boolean isCurrentTimestampSelectStringCallable()
Should the value returned by getCurrentTimestampSelectString() be treated as callable.
boolean isLockTimeoutParameterized()
If this dialect supports specifying lock timeouts, are those timeouts rendered into the SQL string as parameters.
char openQuote()
The character specific to this dialect used to begin a quoted identifier.
Boolean performTemporaryTableDDLInIsolation()
Does the dialect require that temporary table DDL statements occur in isolation from other statements? This would be the case if the creation would cause any current transaction to get committed implicitly.
boolean qualifyIndexName()
Do we need to qualify index names with the schema name?
final String quote(String name)
Apply dialect-specific quoting.
int registerResultSetOutParameter(CallableStatement statement, int position)
Registers an OUT parameter which will be returning a ResultSet.
boolean replaceResultVariableInOrderByClauseWithPosition()
Does this dialect require that references to result variables (i.e, select expresssion aliases) in an ORDER BY clause be replaced by column positions (1-origin) as defined by the select clause?
boolean requiresCastingOfParametersInSelectClause()
Does this dialect require that parameters appearing in the SELECT clause be wrapped in cast() calls to tell the db parser the expected type.
boolean supportsBindAsCallableArgument()
Does this dialect support using a JDBC bind parameter as an argument to a function or procedure call?
boolean supportsCascadeDelete()
boolean supportsCircularCascadeDeleteConstraints()
Does this dialect support definition of cascade delete constraints which can cause circular chains?
boolean supportsColumnCheck()
Does this dialect support column-level check constraints?
boolean supportsCommentOn()
boolean supportsCurrentTimestampSelection()
Does this dialect support a way to retrieve the database's current timestamp value?
boolean supportsEmptyInList()
Does this dialect support empty IN lists?

For example, is [where XYZ in ()] a supported construct?

boolean supportsExistsInSelect()
Does the dialect support an exists statement in the select clause?
boolean supportsExpectedLobUsagePattern()
Expected LOB usage pattern is such that I can perform an insert via prepared statement with a parameter binding for a LOB value without crazy casting to JDBC driver implementation-specific classes...
boolean supportsIdentityColumns()
Does this dialect support identity column key generation?
boolean supportsIfExistsAfterTableName()
boolean supportsIfExistsBeforeTableName()
boolean supportsInsertSelectIdentity()
Does the dialect support some form of inserting and selecting the generated IDENTITY value all in the same statement.
boolean supportsLimit()
Does this dialect support some form of limiting query results via a SQL clause?
boolean supportsLimitOffset()
Does this dialect's LIMIT support (if any) additionally support specifying an offset?
boolean supportsLobValueChangePropogation()
Does the dialect support propagating changes to LOB values back to the database? Talking about mutating the internal value of the locator as opposed to supplying a new locator instance...
boolean supportsLockTimeouts()
Informational metadata about whether this dialect is known to support specifying timeouts for requested lock acquisitions.
boolean supportsNotNullUnique()
boolean supportsOuterJoinForUpdate()
Does this dialect support FOR UPDATE in conjunction with outer joined rows?
boolean supportsParametersInInsertSelect()
Does this dialect support parameters within the SELECT clause of INSERT ...
boolean supportsPooledSequences()
Does this dialect support "pooled" sequences.
boolean supportsResultSetPositionQueryMethodsOnForwardOnlyCursor()
Does this dialect support asking the result set its positioning information on forward only cursors.
boolean supportsRowValueConstructorSyntax()
Is this dialect known to support what ANSI-SQL terms "row value constructor" syntax; sometimes called tuple syntax.
boolean supportsRowValueConstructorSyntaxInInList()
If the dialect supports row values, does it offer such support in IN lists as well?

For example, "...

boolean supportsSequences()
Does this dialect support sequences?
boolean supportsSubqueryOnMutatingTable()
Does this dialect support referencing the table being mutated in a subquery.
boolean supportsSubselectAsInPredicateLHS()
Are subselects supported as the left-hand-side (LHS) of IN-predicates.
boolean supportsTableCheck()
Does this dialect support table-level check constraints?
boolean supportsTemporaryTables()
Does this dialect support temporary tables?
boolean supportsTupleCounts()
Does this dialect support `count(a,b)`?
boolean supportsTupleDistinctCounts()
Does this dialect support `count(distinct a,b)`?
boolean supportsUnboundedLobLocatorMaterialization()
Is it supported to materialize a LOB locator outside the transaction in which it was created?

Again, part of the trickiness here is the fact that this is largely driver dependent.

boolean supportsUnionAll()
Does this dialect support UNION ALL, which is generally a faster variant of UNION?
boolean supportsUnique()
Does this dialect support the UNIQUE column syntax?
boolean supportsUniqueConstraintInCreateAlterTable()
Does this dialect support adding Unique constraints via create and alter table ?
boolean supportsVariableLimit()
Does this dialect support bind variables (i.e., prepared statement parameters) for its limit/offset?
String toBooleanValueString(boolean bool)
The SQL literal value to which this database maps boolean values.
String toString()
String transformSelectString(String select)
Meant as a means for end users to affect the select strings being sent to the database and perhaps manipulate them in some fashion.
boolean useInputStreamToInsertBlob()
Should LOBs (both BLOB and CLOB) be bound using stream operations (i.e.
boolean useMaxForLimit()
Does the LIMIT clause take a "maximum" row number instead of a total number of returned rows?

This is easiest understood via an example.

Protected Methods
final void addTypeOverride(BasicType typeOverride)
String getCreateSequenceString(String sequenceName, int initialValue, int incrementSize)
Overloaded form of getCreateSequenceString(String), additionally taking the initial value and increment size to be applied to the sequence definition.
String getCreateSequenceString(String sequenceName)
Typically dialects which support sequences can create a sequence with a single command.
String getDropSequenceString(String sequenceName)
Typically dialects which support sequences can drop a sequence with a single command.
String getIdentityColumnString()
The syntax used during DDL to define a column as being an IDENTITY.
String getIdentitySelectString()
Get the select command to use to retrieve the last generated IDENTITY value.
String getLimitString(String query, boolean hasOffset)
Apply s limit clause to the query.
void registerColumnType(int code, int capacity, String name)
Subclasses register a type name for the given type code and maximum column length.
void registerColumnType(int code, String name)
Subclasses register a type name for the given type code.
void registerFunction(String name, SQLFunction function)
void registerHibernateType(int code, String name)
Registers a Hibernate Type name for the given java.sql.Types type code.
void registerHibernateType(int code, int capacity, String name)
Registers a Hibernate Type name for the given java.sql.Types type code and maximum column length.
void registerKeyword(String word)
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final String CLOSED_QUOTE

Constant Value: "`"]"

public static final String DEFAULT_BATCH_SIZE

Constant Value: "15"

public static final String NO_BATCH

Constant Value: "0"

public static final String QUOTE

Characters used for quoting SQL identifiers

Constant Value: "`"["

Protected Constructors

protected Dialect ()

Public Methods

public String appendIdentitySelectToInsert (String insertString)

Provided we supportsInsertSelectIdentity(), then attach the "select identity" clause to the insert statement.

Note, if supportsInsertSelectIdentity() == false then the insert-string should be returned without modification.

Parameters
insertString The insert command
Returns
  • The insert command with any necessary identity select clause attached.

public String appendLockHint (LockMode mode, String tableName)

Some dialects support an alternative means to SELECT FOR UPDATE, whereby a "lock hint" is appends to the table name in the from clause.

contributed by Helge Schulz

Parameters
mode The lock mode to apply
tableName The name of the table to which to apply the lock hint.
Returns
  • The table with any required lock hints.

public String applyLocksToSql (String sql, LockOptions aliasedLockOptions, Map keyColumnNames)

Modifies the given SQL by applying the appropriate updates for the specified lock modes and key columns.

The behavior here is that of an ANSI SQL SELECT FOR UPDATE. This method is really intended to allow dialects which do not support SELECT FOR UPDATE to achieve this in their own fashion.

Parameters
sql the SQL string to modify
aliasedLockOptions lock options indexed by aliased table names.
keyColumnNames a map of key columns indexed by aliased table names.
Returns
  • the modified SQL string.

public boolean areStringComparisonsCaseInsensitive ()

Are string comparisons implicitly case insensitive.

In other words, does [where 'XYZ' = 'xyz'] resolve to true?

Returns
  • True if comparisons are case insensitive.

public boolean bindLimitParametersFirst ()

Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?

Returns
  • true if limit parameters should come before other parameters

public boolean bindLimitParametersInReverseOrder ()

ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit. Does this dialect require us to bind the parameters in reverse order?

Returns
  • true if the correct order is limit, offset

public SQLExceptionConverter buildSQLExceptionConverter ()

Build an instance of the SQLExceptionConverter preferred by this dialect for converting SQLExceptions into Hibernate's JDBCException hierarchy. The default Dialect implementation simply returns a converter based on X/Open SQLState codes.

It is strongly recommended that specific Dialect implementations override this method, since interpretation of a SQL error is much more accurate when based on the ErrorCode rather than the SQLState. Unfortunately, the ErrorCode is a vendor- specific approach.

Returns
  • The Dialect's preferred SQLExceptionConverter.

public char closeQuote ()

The character specific to this dialect used to close a quoted identifier.

Returns
  • The dialect's specific close quote character.

public int convertToFirstRowValue (int zeroBasedFirstResult)

Hibernate APIs explicitly state that setFirstResult() should be a zero-based offset. Here we allow the Dialect a chance to convert that value based on what the underlying db or driver will expect.

NOTE: what gets passed into getLimitString(String, int, int) is the zero-based offset. Dialects which do not supportsVariableLimit() should take care to perform any needed convertToFirstRowValue(int) calls prior to injecting the limit values into the SQL string.

Parameters
zeroBasedFirstResult The user-supplied, zero-based first row offset.
Returns
  • The corresponding db/dialect specific offset.

public CaseFragment createCaseFragment ()

Create a CaseFragment strategy responsible for handling this dialect's variations in how CASE statements are handled.

Returns

public JoinFragment createOuterJoinFragment ()

Create a JoinFragment strategy responsible for handling this dialect's variations in how joins are handled.

Returns

public boolean doesReadCommittedCauseWritersToBlockReaders ()

For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?

Returns
  • True if writers block readers to achieve READ_COMMITTED; false otherwise.

public boolean doesRepeatableReadCauseReadersToBlockWriters ()

For the underlying database, is REPEATABLE_READ isolation implemented by forcing writers to wait for read locks to be released?

Returns
  • True if readers block writers to achieve REPEATABLE_READ; false otherwise.

public boolean dropConstraints ()

Do we need to drop constraints before dropping tables in this dialect?

Returns
  • True if constraints must be dropped prior to dropping the table; false otherwise.

public boolean dropTemporaryTableAfterUse ()

Do we need to drop the temporary table after use?

Returns
  • True if the table should be dropped.

public boolean forUpdateOfColumns ()

Is FOR UPDATE OF syntax supported?

Returns
  • True if the database supports FOR UPDATE OF syntax; false otherwise.

public boolean forceLimitUsage ()

Generally, if there is no limit applied to a Hibernate query we do not apply any limits to the SQL query. This option forces that the limit be written to the SQL query.

Returns
  • True to force limit into SQL query even if none specified in Hibernate query; false otherwise.

public String generateTemporaryTableName (String baseTableName)

Generate a temporary table name given the base table.

Parameters
baseTableName The table name from which to base the temp table name.
Returns
  • The generated temp table name.

public String getAddColumnString ()

The syntax used to add a column to a table (optional).

Returns
  • The "add column" fragment.

public String getAddForeignKeyConstraintString (String constraintName, String[] foreignKey, String referencedTable, String[] primaryKey, boolean referencesPrimaryKey)

The syntax used to add a foreign key constraint to a table.

Parameters
constraintName The FK constraint name.
foreignKey The names of the columns comprising the FK
referencedTable The table referenced by the FK
primaryKey The explicit columns in the referencedTable referenced by this FK.
referencesPrimaryKey if false, constraint should be explicit about which column names the constraint refers to
Returns
  • the "add FK" fragment

public String getAddPrimaryKeyConstraintString (String constraintName)

The syntax used to add a primary key constraint to a table.

Parameters
constraintName The name of the PK constraint.
Returns
  • The "add PK" fragment

public String getCascadeConstraintsString ()

Completely optional cascading drop clause

Returns
  • String

public String getCastTypeName (int code)

Get the name of the database type appropriate for casting operations (via the CAST() SQL function) for the given java.sql.Types typecode.

Parameters
code The java.sql.Types typecode
Returns
  • The database type name

public String getColumnComment (String comment)

public String getCreateMultisetTableString ()

Slight variation on getCreateTableString(). Here, we have the command used to create a table when there is no primary key and duplicate rows are expected.

Most databases do not care about the distinction; originally added for Teradata support which does care.

Returns
  • The command used to create a multiset table.

public String[] getCreateSequenceStrings (String sequenceName)

This method is deprecated.
Use getCreateSequenceString(String, int, int) instead

The multiline script used to create a sequence.

Parameters
sequenceName The name of the sequence
Returns
  • The sequence creation commands
Throws
MappingException If sequences are not supported.

public String[] getCreateSequenceStrings (String sequenceName, int initialValue, int incrementSize)

An optional multi-line form for databases which supportsPooledSequences().

Parameters
sequenceName The name of the sequence
initialValue The initial value to apply to 'create sequence' statement
incrementSize The increment value to apply to 'create sequence' statement
Returns
  • The sequence creation commands
Throws
MappingException If sequences are not supported.

public String getCreateTableString ()

Command used to create a table.

Returns
  • The command used to create a table.

public String getCreateTemporaryTablePostfix ()

Get any fragments needing to be postfixed to the command for temporary table creation.

Returns
  • Any required postfix.

public String getCreateTemporaryTableString ()

Command used to create a temporary table.

Returns
  • The command used to create a temporary table.

public String getCrossJoinSeparator ()

Get the separator to use for defining cross joins when translating HQL queries.

Typically this will be either [ cross join ] or [, ]

Note that the spaces are important!

public String getCurrentTimestampSQLFunctionName ()

The name of the database-specific SQL function for retrieving the current timestamp.

Returns
  • The function name.

public String getCurrentTimestampSelectString ()

Retrieve the command used to retrieve the current timestamp from the database.

Returns
  • The command.

public final Properties getDefaultProperties ()

Retrieve a set of default Hibernate properties for this database.

Returns
  • a set of Hibernate properties

public static Dialect getDialect ()

Get an instance of the dialect specified by the current System properties.

Returns
  • The specified Dialect
Throws
HibernateException If no dialect was specified, or if it could not be instantiated.

public static Dialect getDialect (Properties props)

Get an instance of the dialect specified by the given properties or by the current System properties.

Parameters
props The properties to use for finding the dialect class to use.
Returns
  • The specified Dialect
Throws
HibernateException If no dialect was specified, or if it could not be instantiated.

public String getDropForeignKeyString ()

public String[] getDropSequenceStrings (String sequenceName)

The multiline script used to drop a sequence.

Parameters
sequenceName The name of the sequence
Returns
  • The sequence drop commands
Throws
MappingException If sequences are not supported.

public String getDropTemporaryTableString ()

Command used to drop a temporary table.

Returns
  • The command used to drop a temporary table.

public String getForUpdateNowaitString ()

Retrieves the FOR UPDATE NOWAIT syntax specific to this dialect.

Returns
  • The appropriate FOR UPDATE NOWAIT clause string.

public String getForUpdateNowaitString (String aliases)

Get the FOR UPDATE OF column_list NOWAIT fragment appropriate for this dialect given the aliases of the columns to be write locked.

Parameters
aliases The columns to be write locked.
Returns
  • The appropriate FOR UPDATE colunm_list NOWAIT clause string.

public String getForUpdateString ()

Get the string to append to SELECT statements to acquire locks for this dialect.

Returns
  • The appropriate FOR UPDATE clause string.

public String getForUpdateString (String aliases)

Get the FOR UPDATE OF column_list fragment appropriate for this dialect given the aliases of the columns to be write locked.

Parameters
aliases The columns to be write locked.
Returns
  • The appropriate FOR UPDATE OF column_list clause string.

public String getForUpdateString (LockOptions lockOptions)

Given LockOptions (lockMode, timeout), determine the appropriate for update fragment to use.

Parameters
lockOptions contains the lock mode to apply.
Returns
  • The appropriate for update fragment.

public String getForUpdateString (String aliases, LockOptions lockOptions)

Get the FOR UPDATE OF column_list fragment appropriate for this dialect given the aliases of the columns to be write locked.

Parameters
aliases The columns to be write locked.
Returns
  • The appropriate FOR UPDATE OF column_list clause string.

public String getForUpdateString (LockMode lockMode)

Given a lock mode, determine the appropriate for update fragment to use.

Parameters
lockMode The lock mode to apply.
Returns
  • The appropriate for update fragment.

public final Map<StringSQLFunction> getFunctions ()

Retrieves a map of the dialect's registered functions (functionName => SQLFunction).

Returns
  • The map of registered functions.

public String getHibernateTypeName (int code, int length, int precision, int scale)

Get the name of the Hibernate Type associated with the given java.sql.Types typecode with the given storage specification parameters.

Parameters
code The java.sql.Types typecode
length The datatype length
precision The datatype precision
scale The datatype scale
Returns
  • The Hibernate Type name.
Throws
HibernateException If no mapping was specified for that type.

public String getHibernateTypeName (int code)

Get the name of the Hibernate Type associated with the given java.sql.Types typecode.

Parameters
code The java.sql.Types typecode
Returns
  • The Hibernate Type name.
Throws
HibernateException If no mapping was specified for that type.

public String getIdentityColumnString (int type)

The syntax used during DDL to define a column as being an IDENTITY of a particular type.

Parameters
type The java.sql.Types type code.
Returns
  • The appropriate DDL fragment.
Throws
MappingException If IDENTITY generation is not supported.

public String getIdentityInsertString ()

The keyword used to insert a generated value into an identity column (or null). Need if the dialect does not support inserts that specify no column values.

Returns
  • The appropriate keyword.

public String getIdentitySelectString (String table, String column, int type)

Get the select command to use to retrieve the last generated IDENTITY value for a particular table

Parameters
table The table into which the insert was done
column The PK column.
type The java.sql.Types type code.
Returns
  • The appropriate select command
Throws
MappingException If IDENTITY generation is not supported.

public Set<String> getKeywords ()

public String getLimitString (String query, int offset, int limit)

Given a limit and an offset, apply the limit clause to the query.

Parameters
query The query to which to apply the limit.
offset The offset of the limit
limit The limit of the limit ;)
Returns
  • The modified query statement with the limit applied.

public LockingStrategy getLockingStrategy (Lockable lockable, LockMode lockMode)

Get a strategy instance which knows how to acquire a database-level lock of the specified mode for this dialect.

Parameters
lockable The persister for the entity to be locked.
lockMode The type of lock to be acquired.
Returns
  • The appropriate locking strategy.

public String getLowercaseFunction ()

The name of the SQL function that transforms a string to lowercase

Returns
  • The dialect-specific lowercase function.

public int getMaxAliasLength ()

What is the maximum length Hibernate can use for generated aliases?

Returns
  • The maximum length.

public Class getNativeIdentifierGeneratorClass ()

The class (which implements IdentifierGenerator) which acts as this dialects native generation strategy.

Comes into play whenever the user specifies the native generator.

Returns
  • The native generator class.

public String getNoColumnsInsertString ()

The fragment used to insert a row without specifying any column values. This is not possible on some databases.

Returns
  • The appropriate empty values clause.

public String getNullColumnString ()

The keyword used to specify a nullable column.

Returns
  • String

public String getQuerySequencesString ()

Get the select command used retrieve the names of all sequences.

Returns
  • The select command; or null if sequences are not supported.
See Also

public String getReadLockString (int timeout)

Get the string to append to SELECT statements to acquire WRITE locks for this dialect. Location of the of the returned string is treated the same as getForUpdateString.

Parameters
timeout in milliseconds, -1 for indefinite wait and 0 for no wait.
Returns
  • The appropriate LOCK clause string.

public ResultSet getResultSet (CallableStatement statement)

Given a callable statement previously processed by registerResultSetOutParameter(CallableStatement, int), extract the ResultSet from the OUT parameter.

Parameters
statement The callable statement.
Returns
  • The extracted result set.
Throws
SQLException Indicates problems extracting the result set.

public String getSelectClauseNullString (int sqlType)

Given a java.sql.Types type code, determine an appropriate null value to use in a select clause.

One thing to consider here is that certain databases might require proper casting for the nulls here since the select here will be part of a UNION/UNION ALL.

Parameters
sqlType The java.sql.Types type code.
Returns
  • The appropriate select clause value fragment.

public String getSelectGUIDString ()

Get the command used to select a GUID from the underlying database.

Optional operation.

Returns
  • The appropriate command.

public String getSelectSequenceNextValString (String sequenceName)

Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement.

This differs from getSequenceNextValString(String) in that this should return an expression usable within another statement.

Parameters
sequenceName the name of the sequence
Returns
  • The "nextval" fragment.
Throws
MappingException If sequences are not supported.

public String getSequenceNextValString (String sequenceName)

Generate the appropriate select statement to to retrieve the next value of a sequence.

This should be a "stand alone" select statement.

Parameters
sequenceName the name of the sequence
Returns
  • String The "nextval" select string.
Throws
MappingException If sequences are not supported.

public String getTableComment (String comment)

public String getTableTypeString ()

public String getTypeName (int code)

Get the name of the database type associated with the given java.sql.Types typecode.

Parameters
code The java.sql.Types typecode
Returns
  • the database type name
Throws
HibernateException If no mapping was specified for that type.

public String getTypeName (int code, int length, int precision, int scale)

Get the name of the database type associated with the given java.sql.Types typecode with the given storage specification parameters.

Parameters
code The java.sql.Types typecode
length The datatype length
precision The datatype precision
scale The datatype scale
Returns
  • the database type name
Throws
HibernateException If no mapping was specified for that type.

public final List<BasicType> getTypeOverrides ()

Retrieve dialect-specific types for overriding "basic" types.

Returns
  • the dialect-specific types

public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter ()

public String getWriteLockString (int timeout)

Get the string to append to SELECT statements to acquire WRITE locks for this dialect. Location of the of the returned string is treated the same as getForUpdateString.

Parameters
timeout in milliseconds, -1 for indefinite wait and 0 for no wait.
Returns
  • The appropriate LOCK clause string.

public boolean hasAlterTable ()

Does this dialect support the ALTER TABLE syntax?

Returns
  • True if we support altering of tables; false otherwise.

public boolean hasDataTypeInIdentityColumn ()

Whether this dialect have an Identity clause added to the data type or a completely separate identity data type

Returns
  • boolean

public boolean hasSelfReferentialForeignKeyBug ()

public boolean isCurrentTimestampSelectStringCallable ()

Should the value returned by getCurrentTimestampSelectString() be treated as callable. Typically this indicates that JDBC escape syntax is being used...

Returns

public boolean isLockTimeoutParameterized ()

If this dialect supports specifying lock timeouts, are those timeouts rendered into the SQL string as parameters. The implication is that Hibernate will need to bind the timeout value as a parameter in the PreparedStatement. If true, the param position is always handled as the last parameter; if the dialect specifies the lock timeout elsewhere in the SQL statement then the timeout value should be directly rendered into the statement and this method should return false.

Returns
  • True if the lock timeout is rendered into the SQL string as a parameter; false otherwise.

public char openQuote ()

The character specific to this dialect used to begin a quoted identifier.

Returns
  • The dialect's specific open quote character.

public Boolean performTemporaryTableDDLInIsolation ()

Does the dialect require that temporary table DDL statements occur in isolation from other statements? This would be the case if the creation would cause any current transaction to get committed implicitly.

JDBC defines a standard way to query for this information via the dataDefinitionCausesTransactionCommit() method. However, that does not distinguish between temporary table DDL and other forms of DDL; MySQL, for example, reports DDL causing a transaction commit via its driver, even though that is not the case for temporary table DDL.

Possible return values and their meanings:

  • TRUE - Unequivocally, perform the temporary table DDL in isolation.
  • FALSE - Unequivocally, do not perform the temporary table DDL in isolation.
  • null - defer to the JDBC driver response in regards to dataDefinitionCausesTransactionCommit()

Returns
  • see the result matrix above.

public boolean qualifyIndexName ()

Do we need to qualify index names with the schema name?

Returns
  • boolean

public final String quote (String name)

Apply dialect-specific quoting.

By default, the incoming value is checked to see if its first character is the back-tick (`). If so, the dialect specific quoting is applied.

Parameters
name The value to be quoted.
Returns
  • The quoted (or unmodified, if not starting with back-tick) value.

public int registerResultSetOutParameter (CallableStatement statement, int position)

Registers an OUT parameter which will be returning a ResultSet. How this is accomplished varies greatly from DB to DB, hence its inclusion (along with getResultSet(CallableStatement)) here.

Parameters
statement The callable statement.
position The bind position at which to register the OUT param.
Returns
  • The number of (contiguous) bind positions used.
Throws
SQLException Indicates problems registering the OUT param.

public boolean replaceResultVariableInOrderByClauseWithPosition ()

Does this dialect require that references to result variables (i.e, select expresssion aliases) in an ORDER BY clause be replaced by column positions (1-origin) as defined by the select clause?

Returns
  • true if result variable references in the ORDER BY clause should be replaced by column positions; false otherwise.

public boolean requiresCastingOfParametersInSelectClause ()

Does this dialect require that parameters appearing in the SELECT clause be wrapped in cast() calls to tell the db parser the expected type.

Returns
  • True if select clause parameter must be cast()ed

public boolean supportsBindAsCallableArgument ()

Does this dialect support using a JDBC bind parameter as an argument to a function or procedure call?

Returns
  • True if the database supports accepting bind params as args; false otherwise.

public boolean supportsCascadeDelete ()

public boolean supportsCircularCascadeDeleteConstraints ()

Does this dialect support definition of cascade delete constraints which can cause circular chains?

Returns
  • True if circular cascade delete constraints are supported; false otherwise.

public boolean supportsColumnCheck ()

Does this dialect support column-level check constraints?

Returns
  • True if column-level CHECK constraints are supported; false otherwise.

public boolean supportsCommentOn ()

public boolean supportsCurrentTimestampSelection ()

Does this dialect support a way to retrieve the database's current timestamp value?

Returns
  • True if the current timestamp can be retrieved; false otherwise.

public boolean supportsEmptyInList ()

Does this dialect support empty IN lists?

For example, is [where XYZ in ()] a supported construct?

Returns
  • True if empty in lists are supported; false otherwise.

public boolean supportsExistsInSelect ()

Does the dialect support an exists statement in the select clause?

Returns
  • True if exists checks are allowed in the select clause; false otherwise.

public boolean supportsExpectedLobUsagePattern ()

Expected LOB usage pattern is such that I can perform an insert via prepared statement with a parameter binding for a LOB value without crazy casting to JDBC driver implementation-specific classes...

Part of the trickiness here is the fact that this is largely driver dependent. For example, Oracle (which is notoriously bad with LOB support in their drivers historically) actually does a pretty good job with LOB support as of the 10.2.x versions of their drivers...

Returns
  • True if normal LOB usage patterns can be used with this driver; false if driver-specific hookiness needs to be applied.

public boolean supportsIdentityColumns ()

Does this dialect support identity column key generation?

Returns
  • True if IDENTITY columns are supported; false otherwise.

public boolean supportsIfExistsAfterTableName ()

public boolean supportsIfExistsBeforeTableName ()

public boolean supportsInsertSelectIdentity ()

Does the dialect support some form of inserting and selecting the generated IDENTITY value all in the same statement.

Returns
  • True if the dialect supports selecting the just generated IDENTITY in the insert statement.

public boolean supportsLimit ()

Does this dialect support some form of limiting query results via a SQL clause?

Returns
  • True if this dialect supports some form of LIMIT.

public boolean supportsLimitOffset ()

Does this dialect's LIMIT support (if any) additionally support specifying an offset?

Returns
  • True if the dialect supports an offset within the limit support.

public boolean supportsLobValueChangePropogation ()

Does the dialect support propagating changes to LOB values back to the database? Talking about mutating the internal value of the locator as opposed to supplying a new locator instance...

For BLOBs, the internal value might be changed by: setBinaryStream(long), setBytes(long, byte[]), setBytes(long, byte[], int, int), or truncate(long).

For CLOBs, the internal value might be changed by: setAsciiStream(long), setCharacterStream(long), setString(long, String), setString(long, String, int, int), or truncate(long).

NOTE : I do not know the correct answer currently for databases which (1) are not part of the cruise control process or (2) do not supportsExpectedLobUsagePattern().

Returns
  • True if the changes are propagated back to the database; false otherwise.

public boolean supportsLockTimeouts ()

Informational metadata about whether this dialect is known to support specifying timeouts for requested lock acquisitions.

Returns
  • True is this dialect supports specifying lock timeouts.

public boolean supportsNotNullUnique ()

public boolean supportsOuterJoinForUpdate ()

Does this dialect support FOR UPDATE in conjunction with outer joined rows?

Returns
  • True if outer joined rows can be locked via FOR UPDATE.

public boolean supportsParametersInInsertSelect ()

Does this dialect support parameters within the SELECT clause of INSERT ... SELECT ... statements?

Returns
  • True if this is supported; false otherwise.

public boolean supportsPooledSequences ()

Does this dialect support "pooled" sequences. Not aware of a better name for this. Essentially can we specify the initial and increment values?

Returns
  • True if such "pooled" sequences are supported; false otherwise.

public boolean supportsResultSetPositionQueryMethodsOnForwardOnlyCursor ()

Does this dialect support asking the result set its positioning information on forward only cursors. Specifically, in the case of scrolling fetches, Hibernate needs to use isAfterLast() and isBeforeFirst(). Certain drivers do not allow access to these methods for forward only cursors.

NOTE : this is highly driver dependent!

Returns

public boolean supportsRowValueConstructorSyntax ()

Is this dialect known to support what ANSI-SQL terms "row value constructor" syntax; sometimes called tuple syntax.

Basically, does it support syntax like "... where (FIRST_NAME, LAST_NAME) = ('Steve', 'Ebersole') ...".

Returns
  • True if this SQL dialect is known to support "row value constructor" syntax; false otherwise.

public boolean supportsRowValueConstructorSyntaxInInList ()

If the dialect supports row values, does it offer such support in IN lists as well?

For example, "... where (FIRST_NAME, LAST_NAME) IN ( (?, ?), (?, ?) ) ..."

Returns
  • True if this SQL dialect is known to support "row value constructor" syntax in the IN list; false otherwise.

public boolean supportsSequences ()

Does this dialect support sequences?

Returns
  • True if sequences supported; false otherwise.

public boolean supportsSubqueryOnMutatingTable ()

Does this dialect support referencing the table being mutated in a subquery. The "table being mutated" is the table referenced in an UPDATE or a DELETE query. And so can that table then be referenced in a subquery of said UPDATE/DELETE query.

For example, would the following two syntaxes be supported:

  • delete from TABLE_A where ID not in ( select ID from TABLE_A )
  • update TABLE_A set NON_ID = 'something' where ID in ( select ID from TABLE_A)

Returns
  • True if this dialect allows references the mutating table from a subquery.

public boolean supportsSubselectAsInPredicateLHS ()

Are subselects supported as the left-hand-side (LHS) of IN-predicates.

In other words, is syntax like "... IN (1, 2, 3) ..." supported?

Returns
  • True if subselects can appear as the LHS of an in-predicate; false otherwise.

public boolean supportsTableCheck ()

Does this dialect support table-level check constraints?

Returns
  • True if table-level CHECK constraints are supported; false otherwise.

public boolean supportsTemporaryTables ()

Does this dialect support temporary tables?

Returns
  • True if temp tables are supported; false otherwise.

public boolean supportsTupleCounts ()

Does this dialect support `count(a,b)`?

Returns
  • True if the database supports counting tuples; false otherwise.

public boolean supportsTupleDistinctCounts ()

Does this dialect support `count(distinct a,b)`?

Returns
  • True if the database supports counting disintct tuples; false otherwise.

public boolean supportsUnboundedLobLocatorMaterialization ()

Is it supported to materialize a LOB locator outside the transaction in which it was created?

Again, part of the trickiness here is the fact that this is largely driver dependent.

NOTE: all database I have tested which supportsExpectedLobUsagePattern() also support the ability to materialize a LOB outside the owning transaction...

Returns
  • True if unbounded materialization is supported; false otherwise.

public boolean supportsUnionAll ()

Does this dialect support UNION ALL, which is generally a faster variant of UNION?

Returns
  • True if UNION ALL is supported; false otherwise.

public boolean supportsUnique ()

Does this dialect support the UNIQUE column syntax?

Returns
  • boolean

public boolean supportsUniqueConstraintInCreateAlterTable ()

Does this dialect support adding Unique constraints via create and alter table ?

Returns
  • boolean

public boolean supportsVariableLimit ()

Does this dialect support bind variables (i.e., prepared statement parameters) for its limit/offset?

Returns
  • True if bind variables can be used; false otherwise.

public String toBooleanValueString (boolean bool)

The SQL literal value to which this database maps boolean values.

Parameters
bool The boolean value
Returns
  • The appropriate SQL literal.

public String toString ()

public String transformSelectString (String select)

Meant as a means for end users to affect the select strings being sent to the database and perhaps manipulate them in some fashion.

The recommend approach is to instead use onPrepareStatement(String).

Parameters
select The select command
Returns
  • The mutated select command, or the same as was passed in.

public boolean useInputStreamToInsertBlob ()

Should LOBs (both BLOB and CLOB) be bound using stream operations (i.e. setBinaryStream(int, InputStream)).

Returns
  • True if BLOBs and CLOBs should be bound using stream operations.

public boolean useMaxForLimit ()

Does the LIMIT clause take a "maximum" row number instead of a total number of returned rows?

This is easiest understood via an example. Consider you have a table with 20 rows, but you only want to retrieve rows number 11 through 20. Generally, a limit with offset would say that the offset = 11 and the limit = 10 (we only want 10 rows at a time); this is specifying the total number of returned rows. Some dialects require that we instead specify offset = 11 and limit = 20, where 20 is the "last" row we want relative to offset (i.e. total number of rows = 20 - 11 = 9)

So essentially, is limit relative from offset? Or is limit absolute?

Returns
  • True if limit is relative from offset; false otherwise.

Protected Methods

protected final void addTypeOverride (BasicType typeOverride)

protected String getCreateSequenceString (String sequenceName, int initialValue, int incrementSize)

Overloaded form of getCreateSequenceString(String), additionally taking the initial value and increment size to be applied to the sequence definition.

The default definition is to suffix getCreateSequenceString(String) with the string: " start with {initialValue} increment by {incrementSize}" where {initialValue} and {incrementSize} are replacement placeholders. Generally dialects should only need to override this method if different key phrases are used to apply the allocation information.

Parameters
sequenceName The name of the sequence
initialValue The initial value to apply to 'create sequence' statement
incrementSize The increment value to apply to 'create sequence' statement
Returns
  • The sequence creation command
Throws
MappingException If sequences are not supported.

protected String getCreateSequenceString (String sequenceName)

Typically dialects which support sequences can create a sequence with a single command. This is convenience form of getCreateSequenceStrings(String) to help facilitate that.

Dialects which support sequences and can create a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to create a sequence should instead override getCreateSequenceStrings(String).

Parameters
sequenceName The name of the sequence
Returns
  • The sequence creation command
Throws
MappingException If sequences are not supported.

protected String getDropSequenceString (String sequenceName)

Typically dialects which support sequences can drop a sequence with a single command. This is convenience form of getDropSequenceStrings(String) to help facilitate that.

Dialects which support sequences and can drop a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to drop a sequence should instead override getDropSequenceStrings(String).

Parameters
sequenceName The name of the sequence
Returns
  • The sequence drop commands
Throws
MappingException If sequences are not supported.

protected String getIdentityColumnString ()

The syntax used during DDL to define a column as being an IDENTITY.

Returns
  • The appropriate DDL fragment.
Throws
MappingException If IDENTITY generation is not supported.

protected String getIdentitySelectString ()

Get the select command to use to retrieve the last generated IDENTITY value.

Returns
  • The appropriate select command
Throws
MappingException If IDENTITY generation is not supported.

protected String getLimitString (String query, boolean hasOffset)

Apply s limit clause to the query.

Typically dialects utilize variable limit clauses when they support limits. Thus, when building the select command we do not actually need to know the limit or the offest since we will just be using placeholders.

Here we do still pass along whether or not an offset was specified so that dialects not supporting offsets can generate proper exceptions. In general, dialects will override one or the other of this method and getLimitString(String, int, int).

Parameters
query The query to which to apply the limit.
hasOffset Is the query requesting an offset?
Returns
  • the modified SQL

protected void registerColumnType (int code, int capacity, String name)

Subclasses register a type name for the given type code and maximum column length. $l in the type name with be replaced by the column length (if appropriate).

Parameters
code The java.sql.Types typecode
capacity The maximum length of database type
name The database type name

protected void registerColumnType (int code, String name)

Subclasses register a type name for the given type code. $l in the type name with be replaced by the column length (if appropriate).

Parameters
code The java.sql.Types typecode
name The database type name

protected void registerFunction (String name, SQLFunction function)

protected void registerHibernateType (int code, String name)

Registers a Hibernate Type name for the given java.sql.Types type code.

Parameters
code The java.sql.Types typecode
name The Hibernate Type name

protected void registerHibernateType (int code, int capacity, String name)

Registers a Hibernate Type name for the given java.sql.Types type code and maximum column length.

Parameters
code The java.sql.Types typecode
capacity The maximum length of database type
name The Hibernate Type name

protected void registerKeyword (String word)