public class

InformixDialect

extends Dialect
java.lang.Object
   ↳ org.hibernate.dialect.Dialect
     ↳ org.hibernate.dialect.InformixDialect

Class Overview

Informix dialect.

Seems to work with Informix Dynamic Server Version 7.31.UD3, Informix JDBC driver version 2.21JC3.

Summary

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Inherited Constants
From class org.hibernate.dialect.Dialect
Public Constructors
InformixDialect()
Creates new InformixDialect instance.
Public Methods
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 getCreateSequenceString(String sequenceName)
Typically dialects which support sequences can create a sequence with a single command.
String getCurrentTimestampSelectString()
Retrieve the command used to retrieve the current timestamp from the database.
String getDropSequenceString(String sequenceName)
Typically dialects which support sequences can drop a sequence with a single command.
String getIdentityColumnString(int type)
The syntax used during DDL to define a column as being an IDENTITY of a particular type.
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
String getLimitString(String querySelect, int offset, int limit)
Given a limit and an offset, apply the limit clause to the query.
String getQuerySequencesString()
Get the select command used retrieve the names of all sequences.
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.
ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter()
boolean hasDataTypeInIdentityColumn()
Whether this dialect have an Identity clause added to the data type or a completely separate identity data type
boolean isCurrentTimestampSelectStringCallable()
Should the value returned by getCurrentTimestampSelectString() be treated as callable.
boolean supportsCurrentTimestampSelection()
Does this dialect support a way to retrieve the database's current timestamp value?
boolean supportsIdentityColumns()
Does this dialect support identity column key generation?
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 supportsPooledSequences()
Does this dialect support "pooled" sequences.
boolean supportsSequences()
Does this dialect support sequences?
boolean supportsVariableLimit()
Does this dialect support bind variables (i.e., prepared statement parameters) for its limit/offset?
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.

[Expand]
Inherited Methods
From class org.hibernate.dialect.Dialect
From class java.lang.Object

Public Constructors

public InformixDialect ()

Creates new InformixDialect instance. Sets up the JDBC / Informix type mappings.

Public Methods

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. Informix constraint name must be at the end.

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
  • String

public String getAddPrimaryKeyConstraintString (String constraintName)

The syntax used to add a primary key constraint to a table. Informix constraint name must be at the end.

Parameters
constraintName The name of the PK constraint.
Returns
  • String

public 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

public String getCurrentTimestampSelectString ()

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

Returns
  • The command.

public 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

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

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

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

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

Parameters
querySelect 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 String getQuerySequencesString ()

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

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

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.

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.

public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter ()

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 isCurrentTimestampSelectStringCallable ()

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

Returns

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 supportsIdentityColumns ()

Does this dialect support identity column key generation?

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

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 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 supportsSequences ()

Does this dialect support sequences?

Returns
  • True if sequences supported; false otherwise.

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 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.