Logical Database Limits


Item Type of Limit Limit Value

Indexes

Maximum per table

Unlimited

Indexes

Total size of indexed column

75% of the database block size minus some overhead

Columns

Per table

1000 columns maximum

Columns

Per index (or clustered index)

32 columns maximum

Columns

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

Partitions

Maximum number of columns in partition key

16 columns

Partitions

Maximum number of partitions allowed per table or index

1024K - 1

Subpartitions

Maximum number of subpartitions in a composite partitioned table

1024K - 1

Rows

Maximum number per table

Unlimited

System Change Numbers (SCNs)

Maximum

281,474,976,710,656, which is 281 trillion SCNs

Stored Packages

Maximum size

Approximately 6,000,000 lines of code.

See Also: Oracle Database PL/SQL Language Reference 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

Tables

Maximum per database

Unlimited


Note:

The limit on how long a SQL statement can be depends on many factors, including database configuration, disk space, and memory

Note:

When an object instance exists in memory, there is no fixed limit on the number of attributes in the object. But the maximum total amount of memory consumed by an object instance is 4 GB.When an object instance is inserted into a table, the attributes are exploded into separate columns in the table, and the Oracle 1000-column limit applies.