java.sql.Blob |
Known Indirect Subclasses |
The representation (mapping) in
the JavaTM programming
language of an SQL
BLOB
value. An SQL BLOB
is a built-in type
that stores a Binary Large Object as a column value in a row of
a database table. By default drivers implement Blob
using
an SQL locator(BLOB)
, which means that a
Blob
object contains a logical pointer to the
SQL BLOB
data rather than the data itself.
A Blob
object is valid for the duration of the
transaction in which is was created.
Methods in the interfaces ResultSet
,
CallableStatement
, and PreparedStatement
, such as
getBlob
and setBlob
allow a programmer to
access an SQL BLOB
value.
The Blob
interface provides methods for getting the
length of an SQL BLOB
(Binary Large Object) value,
for materializing a BLOB
value on the client, and for
determining the position of a pattern of bytes within a
BLOB
value. In addition, this interface has methods for updating
a BLOB
value.
All methods on the Blob
interface must be fully implemented if the
JDBC driver supports the data type.
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
This method frees the
Blob object and releases the resources that
it holds. | |||||||||||
Returns an
InputStream object that contains a partial Blob value,
starting with the byte specified by pos, which is length bytes in length. | |||||||||||
Retrieves the
BLOB value designated by this
Blob instance as a stream. | |||||||||||
Retrieves all or part of the
BLOB
value that this Blob object represents, as an array of
bytes. | |||||||||||
Returns the number of bytes in the
BLOB value
designated by this Blob object. | |||||||||||
Retrieves the byte position in the
BLOB value
designated by this Blob object at which
pattern begins. | |||||||||||
Retrieves the byte position at which the specified byte array
pattern begins within the BLOB
value that this Blob object represents. | |||||||||||
Retrieves a stream that can be used to write to the
BLOB
value that this Blob object represents. | |||||||||||
Writes the given array of bytes to the
BLOB value that
this Blob object represents, starting at position
pos , and returns the number of bytes written. | |||||||||||
Writes all or part of the given
byte array to the
BLOB value that this Blob object represents
and returns the number of bytes written. | |||||||||||
Truncates the
BLOB value that this Blob
object represents to be len bytes in length. |
This method frees the Blob
object and releases the resources that
it holds. The object is invalid once the free
method is called.
After free
has been called, any attempt to invoke a
method other than free
will result in a SQLException
being thrown. If free
is called multiple times, the subsequent
calls to free
are treated as a no-op.
SQLException | if an error occurs releasing the Blob's resources |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Returns an InputStream
object that contains a partial Blob
value,
starting with the byte specified by pos, which is length bytes in length.
pos | the offset to the first byte of the partial value to be retrieved.
The first byte in the Blob is at position 1 |
---|---|
length | the length in bytes of the partial value to be retrieved |
InputStream
through which the partial Blob
value can be read.SQLException | if pos is less than 1 or if pos is greater than the number of bytes
in the Blob or if pos + length is greater than the number of bytes
in the Blob |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Retrieves the BLOB
value designated by this
Blob
instance as a stream.
BLOB
dataSQLException | if there is an error accessing the
BLOB value |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Retrieves all or part of the BLOB
value that this Blob
object represents, as an array of
bytes. This byte
array contains up to length
consecutive bytes starting at position pos
.
pos | the ordinal position of the first byte in the
BLOB value to be extracted; the first byte is at
position 1 |
---|---|
length | the number of consecutive bytes to be copied; the value for length must be 0 or greater |
length
consecutive bytes from the BLOB
value designated
by this Blob
object, starting with the
byte at position pos
SQLException | if there is an error accessing the
BLOB value; if pos is less than 1 or length is
less than 0 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Returns the number of bytes in the BLOB
value
designated by this Blob
object.
BLOB
in bytesSQLException | if there is an error accessing the
length of the BLOB |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Retrieves the byte position in the BLOB
value
designated by this Blob
object at which
pattern
begins. The search begins at position
start
.
pattern | the Blob object designating
the BLOB value for which to search |
---|---|
start | the position in the BLOB value
at which to begin searching; the first position is 1 |
SQLException | if there is an error accessing the
BLOB value or if start is less than 1 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Retrieves the byte position at which the specified byte array
pattern
begins within the BLOB
value that this Blob
object represents. The
search for pattern
begins at position
start
.
pattern | the byte array for which to search |
---|---|
start | the position at which to begin searching; the first position is 1 |
SQLException | if there is an error accessing the
BLOB or if start is less than 1 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Retrieves a stream that can be used to write to the BLOB
value that this Blob
object represents. The stream begins
at position pos
.
The bytes written to the stream will overwrite the existing bytes
in the Blob
object starting at the position
pos
. If the end of the Blob
value is reached
while writing to the stream, then the length of the Blob
value will be increased to accomodate the extra bytes.
Note: If the value specified for pos
is greater then the length+1 of the BLOB
value then the
behavior is undefined. Some JDBC drivers may throw a
SQLException
while other drivers may support this
operation.
pos | the position in the BLOB value at which
to start writing; the first position is 1 |
---|
java.io.OutputStream
object to which data can
be writtenSQLException | if there is an error accessing the
BLOB value or if pos is less than 1 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Writes the given array of bytes to the BLOB
value that
this Blob
object represents, starting at position
pos
, and returns the number of bytes written.
The array of bytes will overwrite the existing bytes
in the Blob
object starting at the position
pos
. If the end of the Blob
value is reached
while writing the array of bytes, then the length of the Blob
value will be increased to accomodate the extra bytes.
Note: If the value specified for pos
is greater then the length+1 of the BLOB
value then the
behavior is undefined. Some JDBC drivers may throw a
SQLException
while other drivers may support this
operation.
pos | the position in the BLOB object at which
to start writing; the first position is 1 |
---|---|
bytes | the array of bytes to be written to the BLOB
value that this Blob object represents |
SQLException | if there is an error accessing the
BLOB value or if pos is less than 1 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Writes all or part of the given byte
array to the
BLOB
value that this Blob
object represents
and returns the number of bytes written.
Writing starts at position pos
in the BLOB
value; len
bytes from the given byte array are written.
The array of bytes will overwrite the existing bytes
in the Blob
object starting at the position
pos
. If the end of the Blob
value is reached
while writing the array of bytes, then the length of the Blob
value will be increased to accomodate the extra bytes.
Note: If the value specified for pos
is greater then the length+1 of the BLOB
value then the
behavior is undefined. Some JDBC drivers may throw a
SQLException
while other drivers may support this
operation.
pos | the position in the BLOB object at which
to start writing; the first position is 1 |
---|---|
bytes | the array of bytes to be written to this BLOB
object |
offset | the offset into the array bytes at which
to start reading the bytes to be set |
len | the number of bytes to be written to the BLOB
value from the array of bytes bytes |
SQLException | if there is an error accessing the
BLOB value or if pos is less than 1 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |
Truncates the BLOB
value that this Blob
object represents to be len
bytes in length.
Note: If the value specified for pos
is greater then the length+1 of the BLOB
value then the
behavior is undefined. Some JDBC drivers may throw a
SQLException
while other drivers may support this
operation.
len | the length, in bytes, to which the BLOB value
that this Blob object represents should be truncated |
---|
SQLException | if there is an error accessing the
BLOB value or if len is less than 0 |
---|---|
SQLFeatureNotSupportedException | if the JDBC driver does not support this method |