Static Data Dictionary Views, 84 of 452

ALL_TAB_COLUMNS

ALL_TAB_COLUMNS describes the columns of all tables, views, and clusters accessible to the user. To gather statistics for this view, use the SQL command ANALYZE.

Related views:

DBA_TAB_COLUMNS describes the columns of all tables, views, and clusters in the database.

USER_TAB_COLUMNS describes the columns of all tables, views, and clusters owned by the current user. This view does not display the OWNER column.

Column Datatype NULL Description

OWNER

VARCHAR2(30)

NOT NULL

Owner of the table, view or cluster

TABLE_NAME

VARCHAR2(30)

NOT NULL

Table, view, or cluster name

COLUMN_NAME

VARCHAR2(30)

NOT NULL

Column name

DATA_TYPE

VARCHAR2(30)

Datatype of the column

DATA_TYPE_MOD

VARCHAR2(3)

Datatype modifier of the column

DATA_TYPE_OWNER

VARCHAR2(30)

Owner of the datatype of the column

DATA_LENGTH

NUMBER

NOT NULL

Length of the column in bytes

DATA_PRECISION

NUMBER

Decimal precision for NUMBER datatype; binary precision for FLOAT datatype, null for all other datatypes

DATA_SCALE

NUMBER

Digits to right of decimal point in a number

NULLABLE

VARCHAR2(1)

Specifies whether a column allows NULLs. Value is N if there is a NOT NULL constraint on the column or if the column is part of a PRIMARY KEY.

COLUMN_ID

NUMBER

NOT NULL

Sequence number of the column as created

DEFAULT_LENGTH

NUMBER

Length of default value for the column

DATA_DEFAULT

LONG

Default value for the column

NUM_DISTINCT

NUMBER

These columns remain for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views. This view now picks up these values from HIST_HEAD$ rather than COL$.

LOW_VALUE

RAW(32)

HIGH_VALUE

RAW(32)

DENSITY

NUMBER

NUM_NULLS

NUMBER

The number of nulls in the column

NUM_BUCKETS

NUMBER

The number of buckets in histogram for the column

LAST_ANALYZED

DATE

The date on which this column was most recently analyzed

SAMPLE_SIZE

The sample size used in analyzing this column

CHARACTER_SET_NAME

VARCHAR2(44)

The name of the character set: CHAR_CS or NCHAR_CS

CHAR_COL_DECL_LENGTH

NUMBER

The length

GLOBAL_STATS

VARCHAR2(3)

For partitioned tables, indicates whether column statistics were collected for the table as a whole (YES) or were estimated from statistics on underlying partitions and subpartitions (NO).

USER_STATS

VARCHAR2(3)

Were the statistics entered directly by the user?

AVG_COL_LEN

NUMBER

The average length of the column, in bytes

Column	Datatype	NULL	Description
`OWNER`	`VARCHAR2(30)`	`NOT NULL`	Owner of the table, view or cluster
`TABLE_NAME`	`VARCHAR2(30)`	`NOT NULL`	Table, view, or cluster name
`COLUMN_NAME`	`VARCHAR2(30)`	`NOT NULL`	Column name
`DATA_TYPE`	`VARCHAR2(30)`		Datatype of the column
`DATA_TYPE_MOD`	`VARCHAR2(3)`		Datatype modifier of the column
`DATA_TYPE_OWNER`	`VARCHAR2(30)`		Owner of the datatype of the column
`DATA_LENGTH`	`NUMBER`	`NOT NULL`	Length of the column in bytes
`DATA_PRECISION`	`NUMBER`		Decimal precision for `NUMBER` datatype; binary precision for `FLOAT` datatype, null for all other datatypes
`DATA_SCALE`	`NUMBER`		Digits to right of decimal point in a number
`NULLABLE`	`VARCHAR2(1)`		Specifies whether a column allows NULLs. Value is N if there is a NOT NULL constraint on the column or if the column is part of a PRIMARY KEY.
`COLUMN_ID`	`NUMBER`	`NOT NULL`	Sequence number of the column as created
`DEFAULT_LENGTH`	`NUMBER`		Length of default value for the column
`DATA_DEFAULT`	`LONG`		Default value for the column
`NUM_DISTINCT`	`NUMBER`		These columns remain for backward compatibility with Oracle7. This information is now in the {`TAB\|PART`}`_COL_STATISTICS` views. This view now picks up these values from `HIST_HEAD`$ rather than `COL`$.
`LOW_VALUE`	`RAW(32)`
`HIGH_VALUE`	`RAW(32)`
`DENSITY`	`NUMBER`
`NUM_NULLS`	`NUMBER`		The number of nulls in the column
`NUM_BUCKETS`	`NUMBER`		The number of buckets in histogram for the column
`LAST_ANALYZED`	`DATE`		The date on which this column was most recently analyzed
`SAMPLE_SIZE`			The sample size used in analyzing this column
`CHARACTER_SET_NAME`	`VARCHAR2(44)`		The name of the character set: `CHAR_CS` or `NCHAR_CS`
`CHAR_COL_DECL_LENGTH`	`NUMBER`		The length
`GLOBAL_STATS`	`VARCHAR2(3)`		For partitioned tables, indicates whether column statistics were collected for the table as a whole (`YES`) or were estimated from statistics on underlying partitions and subpartitions (`NO`).
`USER_STATS`	`VARCHAR2(3)`		Were the statistics entered directly by the user?
`AVG_COL_LEN`	`NUMBER`		The average length of the column, in bytes