Blob
interface Blob
java.sql.Blob |
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.
Summary
Public methods | |
---|---|
abstract Unit |
free() This method frees the |
abstract InputStream! |
Retrieves the |
abstract InputStream! |
getBinaryStream(pos: Long, length: Long) Returns an |
abstract ByteArray! |
Retrieves all or part of the |
abstract Long |
length() Returns the number of bytes in the |
abstract Long |
Retrieves the byte position at which the specified byte array |
abstract Long |
Retrieves the byte position in the |
abstract OutputStream! |
setBinaryStream(pos: Long) Retrieves a stream that can be used to write to the |
abstract Int |
Writes the given array of bytes to the |
abstract Int |
Writes all or part of the given |
abstract Unit |
Truncates the |
Public methods
free
abstract fun free(): Unit
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.
Exceptions | |
---|---|
java.sql.SQLException |
if an error occurs releasing the Blob's resources |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
getBinaryStream
abstract fun getBinaryStream(): InputStream!
Retrieves the BLOB
value designated by this Blob
instance as a stream.
Return | |
---|---|
InputStream! |
a stream containing the BLOB data |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
See Also
getBinaryStream
abstract fun getBinaryStream(
pos: Long,
length: Long
): InputStream!
Returns an InputStream
object that contains a partial Blob
value, starting with the byte specified by pos, which is length bytes in length.
Parameters | |
---|---|
pos |
Long: the offset to the first byte of the partial value to be retrieved. The first byte in the Blob is at position 1 |
length |
Long: the length in bytes of the partial value to be retrieved |
Return | |
---|---|
InputStream! |
InputStream through which the partial Blob value can be read. |
Exceptions | |
---|---|
java.sql.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 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
getBytes
abstract fun getBytes(
pos: Long,
length: Int
): ByteArray!
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
.
Parameters | |
---|---|
pos |
Long: the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1 |
length |
Int: the number of consecutive bytes to be copied; the value for length must be 0 or greater |
Return | |
---|---|
ByteArray! |
a byte array containing up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value; if pos is less than 1 or length is less than 0 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
See Also
length
abstract fun length(): Long
Returns the number of bytes in the BLOB
value designated by this Blob
object.
Return | |
---|---|
Long |
length of the BLOB in bytes |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the length of the BLOB |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
position
abstract fun position(
pattern: ByteArray!,
start: Long
): Long
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
.
Parameters | |
---|---|
pattern |
ByteArray!: the byte array for which to search |
start |
Long: the position at which to begin searching; the first position is 1 |
Return | |
---|---|
Long |
the position at which the pattern appears, else -1 |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB or if start is less than 1 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
position
abstract fun position(
pattern: Blob!,
start: Long
): Long
Retrieves the byte position in the BLOB
value designated by this Blob
object at which pattern
begins. The search begins at position start
.
Parameters | |
---|---|
pattern |
Blob!: the Blob object designating the BLOB value for which to search |
start |
Long: the position in the BLOB value at which to begin searching; the first position is 1 |
Return | |
---|---|
Long |
the position at which the pattern begins, else -1 |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value or if start is less than 1 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
setBinaryStream
abstract fun setBinaryStream(pos: Long): OutputStream!
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.
Parameters | |
---|---|
pos |
Long: the position in the BLOB value at which to start writing; the first position is 1 |
Return | |
---|---|
OutputStream! |
a java.io.OutputStream object to which data can be written |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value or if pos is less than 1 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
See Also
setBytes
abstract fun setBytes(
pos: Long,
bytes: ByteArray!
): Int
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.
Parameters | |
---|---|
pos |
Long: the position in the BLOB object at which to start writing; the first position is 1 |
bytes |
ByteArray!: the array of bytes to be written to the BLOB value that this Blob object represents |
Return | |
---|---|
Int |
the number of bytes written |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value or if pos is less than 1 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
See Also
setBytes
abstract fun setBytes(
pos: Long,
bytes: ByteArray!,
offset: Int,
len: Int
): Int
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.
Parameters | |
---|---|
pos |
Long: the position in the BLOB object at which to start writing; the first position is 1 |
bytes |
ByteArray!: the array of bytes to be written to this BLOB object |
offset |
Int: the offset into the array bytes at which to start reading the bytes to be set |
len |
Int: the number of bytes to be written to the BLOB value from the array of bytes bytes |
Return | |
---|---|
Int |
the number of bytes written |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value or if pos is less than 1 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |
See Also
truncate
abstract fun truncate(len: Long): Unit
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.
Parameters | |
---|---|
len |
Long: the length, in bytes, to which the BLOB value that this Blob object represents should be truncated |
Exceptions | |
---|---|
java.sql.SQLException |
if there is an error accessing the BLOB value or if len is less than 0 |
java.sql.SQLFeatureNotSupportedException |
if the JDBC driver does not support this method |