GROUP BY clause

Maximum length

The GROUP BY expression and all of the nondistinct aggregate functions (for example, SUM, AVG) must fit within a single database block.

Indexes

Maximum per table

Unlimited

total size of indexed column

75% of the database block size minus some overhead

Columns

Per table

1000 columns maximum

Per index (or clustered index)

32 columns maximum

Per bitmapped index

30 columns maximum

Constraints

Maximum per column

Unlimited

Subqueries

Maximum levels of subqueries in a SQL statement

Unlimited in the FROM clause of the top-level query

255 subqueries in the WHERE clause

Partitions

Maximum length of linear partitioning key

4 KB - overhead

Maximum number of columns in partition key

16 columns

Maximum number of partitions allowed per table or index

64 K-1 partitions

Rollback Segments

Maximum number per database

No limit; limited within a session by the MAX_ROLLBACK_SEGMENTS initialization parameter

Rows

Maximum number per table

Unlimited

SQL Statement Length

Maximum length of statements

64 K maximum; particular tools may impose lower limits

Stored Packages

Maximum size

PL/SQL and Developer/2000 may have limits on the size of stored procedures they can call. The limits typically range from 2000 to 3000 lines of code.

See Also: Your PL/SQL or Developer/2000 documentation for details

Trigger Cascade Limit

Maximum value

Operating system-dependent, typically 32

Users and Roles

Maximum

2,147,483,638

Tables

Maximum per clustered table

32 tables

Maximum per database

Unlimited