DBMS_LOB package
The DBMS_LOB package provides the capability to operate on large objects.
In the following sections describing the individual procedures and functions, lengths and offsets are measured in bytes if the large objects are BLOBs. Lengths and offsets are measured in characters if the large objects are CLOBs.
The DBMS_LOB package supports LOB data up to 10M bytes.
The DBMS_LOB package includes the following routines.
| Routine Name | Description |
|---|---|
| APPEND procedure | Appends one large object to another. |
| COMPARE function | Compares two large objects. |
| COPY procedure | Copies one large object to another. |
| ERASE procedure | Erases a large object. |
| GETLENGTH function | Gets the length of the large object. |
| INSTR function | Gets the position of the nth occurrence of a pattern in the large object starting at offset. |
| READ procedure | Reads a large object. |
| SUBSTR function | Gets part of a large object. |
| TRIM procedure | Trims a large object to the specified length. |
| WRITE procedure | Writes data to a large object. |
In partitioned database environments, you will receive
an error if you execute any of the following routines inside a WHERE
clause of a SELECT statement:
- dbms_lob.compare
- dbms_lob.get_storage_limit
- dbms_lob.get_length
- dbms_lob.instr
- dbms_lob.isopen
- dbms_lob.substr
The following table lists the public variables available
in the package.
| Public variables | Data type | Value |
|---|---|---|
| lob_readonly | INTEGER | 0 |
| lob_readwrite | INTEGER | 1 |