Database Limits, 2 of 5

Datatype Limits

Datatypes Limit Comments

BFILE

Maximum size: 4 GB
Maximum size of file name: 255 characters
Maximum size of directory name: 30 characters
Maximum number of open BFILEs: see Comments

The maximum number of BFILEs is limited by the value of SESSION_MAX_OPEN_FILES initialization parameter, which is itself limited by the maximum number of open files the operating system will allow.

BLOB

Maximum size: 4 GB

The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a

CHAR

2000 bytes maximum

CHAR VARYING

4000 bytes

CLOB

4 GB maximum

The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a

Literals (characters or numbers in SQL or PL/SQL)

4000 characters maximum

LONG

2³¹-1 bytes (2 GB) maximum

Only one LONG column allowed per table.

NCHAR

2000 bytes

NCHAR VARYING

4000 bytes

NCLOB

4 GB maximum

The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a

NUMBER

999...(38 9's) x10¹²⁵ maximum value

Can be represented to full 38-digit precision (the mantissa).

-999...(38 9's) x10¹²⁵ minimum value

Can be represented to full 38-digit precision (the mantissa).

Precision

38 significant digits

RAW

2000 bytes maximum

VARCHAR

4000 bytes maximum

VARCHAR2

4000 bytes maximum

a The absolute maximum number of columns in a table is 1000. However, when you create an object table (or a relational table with columns of object, nested table, varray, or REF type), Oracle maps the columns of the user-defined types to relational columns, creating in effect "hidden columns" that count toward the 1000-column limit. For details on how Oracle calculates the total number of columns in such a table, please refer to Oracle8i Administrator's Guide.

Datatypes	Limit	Comments
`BFILE`	Maximum size: 4 GB Maximum size of file name: 255 characters Maximum size of directory name: 30 characters Maximum number of open BFILEs: see Comments	The maximum number of `BFILEs` is limited by the value of `SESSION_MAX_OPEN_FILES` initialization parameter, which is itself limited by the maximum number of open files the operating system will allow.
`BLOB`	Maximum size: 4 GB	The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a
`CHAR`	2000 bytes maximum
`CHAR VARYING`	4000 bytes
`CLOB`	4 GB maximum	The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a
Literals (characters or numbers in SQL or PL/SQL)	4000 characters maximum
`LONG`	2³¹-1 bytes (2 GB) maximum	Only one `LONG` column allowed per table.
`NCHAR`	2000 bytes
`NCHAR VARYING`	4000 bytes
`NCLOB`	4 GB maximum	The number of LOB columns per table is limited only by the maximum number of columns per table (that is, 1000).^a
`NUMBER`	999...(38 9's) x10¹²⁵ maximum value	Can be represented to full 38-digit precision (the mantissa).
`NUMBER`	-999...(38 9's) x10¹²⁵ minimum value	Can be represented to full 38-digit precision (the mantissa).
Precision	38 significant digits
`RAW`	2000 bytes maximum
`VARCHAR`	4000 bytes maximum
`VARCHAR2`	4000 bytes maximum
a The absolute maximum number of columns in a table is 1000. However, when you create an object table (or a relational table with columns of object, nested table, varray, or `REF` type), Oracle maps the columns of the user-defined types to relational columns, creating in effect "hidden columns" that count toward the 1000-column limit. For details on how Oracle calculates the total number of columns in such a table, please refer to Oracle8i Administrator's Guide.