Every table in an Oracle database has a pseudocolumn named ROWID.

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A pseudocolumn behaves like a table column, but is not actually stored in the table. You can select from pseudocolumns, but you cannot insert, update, or delete their values. A pseudocolumn is also similar to a SQL function without arguments. Functions without arguments typically return the same value for every row in the result set, whereas pseudocolumns typically return a different value for each row.

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Values of the ROWID pseudocolumn are strings representing the address of each row. These strings have the data type ROWID. This pseudocolumn is not evident when listing the structure of a table by executing SELECT or DESCRIBE, nor does the pseudocolumn consume space. However, the rowid of each row can be retrieved with a SQL query using the reserved word ROWID as a column name.

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The following example queries the ROWID pseudocolumn to show the rowid of the row in the employees table for employee 100:

CopySQL> SELECT ROWID FROM employees WHERE employee_id = 100;

ROWID
------------------
AAAPecAAFAAAABSAAA

See also

• “Rowid Format”
• Oracle Database Development Guide to learn how to identify rows by address
• Oracle Database SQL Language Reference to learn about rowid types

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