ROWID_TO_EXTENDED Function

This function translates a restricted ROWID that addresses a row in a schema and table that you specify to the extended ROWID format. Later, it may be removed from this package into a different place.

Syntax

DBMS_ROWID.ROWID_TO_EXTENDED (
   old_rowid       IN ROWID,
   schema_name     IN VARCHAR2,   
   object_name     IN VARCHAR2,
   conversion_type IN INTEGER)
  RETURN ROWID;

Pragmas

   pragma RESTRICT_REFERENCES(rowid_to_extended,WNDS,WNPS,RNPS);

Parameters

Table 57-10 ROWID_TO_EXTENDED Function Parameters

Parameter	Description
old_rowid	ROWID to be converted.
schema_name	Name of the schema which contains the table (optional).
object_name	Table name (optional).
conversion_type	rowid_convert_internal/external_convert_external (whether old_rowid was stored in a column of ROWID type, or the character string).

Returns

ROWID_TO_EXTENDED returns the ROWID in the extended character format. If the input ROWID is NULL, then the function returns NULL. If a zero-valued ROWID is supplied (00000000.0000.0000), then a zero-valued restricted ROWID is returned.

Example

Assume that there is a table called RIDS in the schema SCOTT, and that the table contains a column ROWID_COL that holds ROWIDs (restricted), and a column TABLE_COL that point to other tables in the SCOTT schema. You can convert the ROWIDs to extended format with the statement:

UPDATE SCOTT.RIDS

SET rowid_col =
dbms_rowid.rowid_to_extended (
   rowid_col, 'SCOTT", TABLE_COL, 0);

Usage Notes

If the schema and object names are provided as IN parameters, then this function verifies SELECT authority on the table named, and converts the restricted ROWID provided to an extended ROWID, using the data object number of the table. That ROWID_TO_EXTENDED returns a value, however, does not guarantee that the converted ROWID actually references a valid row in the table, either at the time that the function is called, or when the extended ROWID is actually used.

If the schema and object name are not provided (are passed as NULL), then this function attempts to fetch the page specified by the restricted ROWID provided. It treats the file number stored in this ROWID as the absolute file number. This can cause problems if the file has been dropped, and its number has been reused prior to the migration. If the fetched page belongs to a valid table, then the data object number of this table is used in converting to an extended ROWID value. This is very inefficient, and Oracle recommends doing this only as a last resort, when the target table is not known. The user must still know the correct table name at the time of using the converted value.

If an extended ROWID value is supplied, the data object number in the input extended ROWID is verified against the data object number computed from the table name parameter. If the two numbers do not match, the INVALID_ROWID exception is raised. If they do match, the input ROWID is returned.

See Also: The ROWID_VERIFY Function has a method to determine if a given ROWID can be converted to the extended format.