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 sub queries in a SQL statement

Unlimited in the FROM clause of the top-level query

255 sub queries 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

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.

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


Source: Oracle

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