COPY

The COPY stored procedure is used to copy all or part of a source internal LOB to a destination internal LOB.

You can specify the offset of the source LOB and destination LOB, as well as the number of bytes or characters to copy.

Syntax

DBMS_LOB.COPY (
dest_lob    IN OUT NOCOPY BLOB,
src_lob     IN            BLOB,
amount      IN            INTEGER,
dest_offset IN            INTEGER := 1,
src_offset  IN            INTEGER := 1);

DBMS_LOB.COPY (
dest_lob    IN OUT NOCOPY CLOB CHARACTER SET ANY_CS,
src_lob     IN            CLOB CHARACTER SET ANY_CS,
amount      IN            INTEGER,
dest_offset IN            INTEGER := 1,
src_offset  IN            INTEGER := 1);

Parameters

Exceptions

Considerations

• If the specified offset in the destination LOB exceeds the current end of the data in the LOB, zero-byte fillers or spaces are inserted into the destination BLOB or CLOB. If the offset is less than the current length of the destination LOB, the existing data will be overwritten.

• Specifying a quantity that exceeds the length of the data in the source LOB does not result in an error. Therefore, you can specify a large amount of data to copy from the source LOB, which will copy all data from the src_offset to the end of the source LOB.

• It is not mandatory to wrap LOB operations within the Open/Close interface. If the LOB is not opened before the operation, the functional index and domain index on the LOB column will be updated during the call. However, if the LOB is opened before the operation, it must be closed before the transaction is committed. When an internal LOB is closed, the functional index and domain index on the LOB column will be updated.

  If the LOB operation is not wrapped within the Open/Close interface, the functional index and domain index will be updated each time the LOB is written. To avoid performance impact, it is recommended to include LOB write operations within OPEN or CLOSE statements.

• Before copying, if both the source and destination LOB are archived, they will be retrieved first. For a full overwrite, the destination LOB will not be retrieved.