SYS_TYPEID returns the typeid of the most specific type of the operand. This value is used primarily to identify the type-discriminant column underlying a substitutable column. For example, you can use the value returned by SYS_TYPEID to build an index on the type-discriminant column.
You can use this function only on object type operands. All final root object typesâfinal types not belonging to a type hierarchyâhave a null typeid. Oracle Database assigns to all types belonging to a type hierarchy a unique non-null typeid.
The following examples use the tables persons and books, which are created in "Substitutable Table and Column Examples". The first query returns the most specific types of the object instances stored in the persons table.
SELECT name, SYS_TYPEID(VALUE(p)) "Type_id" FROM persons p; NAME Type_id ------------------------- -------------------------------- Bob 01 Joe 02 Tim 03
The next query returns the most specific types of authors stored in the table books:
SELECT b.title, b.author.name, SYS_TYPEID(author) "Type_ID" FROM books b; TITLE AUTHOR.NAME Type_ID ------------------------- -------------------- ------------------- An Autobiography Bob 01 Business Rules Joe 02 Mixing School and Work Tim 03
You can use the SYS_TYPEID function to create an index on the type-discriminant column of a table. For an example, see "Indexing on Substitutable Columns: Examples".
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4