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Updated on 2025-08-19 GMT+08:00
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DB_TAB_COLUMNS

DB_TAB_COLUMNS displays description information about columns of tables and views accessible to the current user. This view exists in the PG_CATALOG and SYS schemas. This view is accessible to all users and displays all information accessible to the current user.

Table 1 DB_TAB_COLUMNS columns

Name

Type

Description

owner

character varying(64)

Table owner.

table_name

character varying(64)

Table name.

column_name

character varying(64)

Column name.

data_type

character varying(128)

Data type of a column.

data_type_mod

character varying(3)

Not supported. The value is NULL.

data_type_owner

character varying(128)

Owner of the data type of a column.

data_length

integer

Length of a column, in bytes.

data_precision

integer

Precision of the data type. It is valid for the numeric data type and NULL for other types.

data_scale

integer

Number of decimal places. It is valid for the numeric data type and 0 for other data types.

nullable

bpchar

Specifies whether the column can be null. The options are as follows:

  • y: yes.
  • n: no. For primary key constraints and NOT NULL constraints, the value is n.

column_id

integer

Sequence number of a column when the table is created.

default_length

numeric

Length of the default value of a column, in bytes.

data_default

text

Default value of a column.

num_distinct

numeric

Number of different values in a column.

low_value

raw

Minimum value in a column.

high_value

raw

Maximum value in a column.

density

numeric

Column density.

num_nulls

numeric

Number of empty values in a column.

num_buckets

numeric

Number of buckets in the histogram of a column.

last_analyzed

date

Last analysis date.

sample_size

numeric

Sample size used to analyze a column.

character_set_name

character varying(44)

Not supported. The value is NULL.

char_col_decl_length

numeric

Declaration length of a column of the character type.

global_stats

character varying(3)

Not supported. The value is NO.

user_stats

character varying(3)

Not supported. The value is NO.

avg_col_len

numeric

Average length of a column, in bytes.

char_length

numeric

Column length (in the unit of bytes) which is valid only for varchar, nvarchar2, bpchar, and char types.

char_used

character varying(1)

Not supported. Set it to B for the varchar, bpchar, or char data type. Set it to C for the nvarchar2 data type. For other data types, set it to NULL.

v80_fmt_image

character varying(3)

Not supported. The value is NULL.

data_upgraded

character varying(3)

Not supported. The value is YES.

histogram

character varying(15)
Specifies whether the histogram exists and the type of the histogram.
  • NONE: no histogram.
  • FREQUENCY: frequency histogram.
  • EQUI_WIDTH: equal-width histogram.

default_on_null

character varying(3)

Not supported. The value is NULL.

identity_column

character varying(3)

Not supported. The value is NULL.

evaluation_edition

character varying(128)

Not supported. The value is NULL.

unusable_before

character varying(128)

Not supported. The value is NULL.

unusable_beginning

character varying(128)

Not supported. The value is NULL.

collation

character varying(100)

Collation rule of a column. This column conflicts with reserved keywords. Therefore, add the view name when calling this column.

comments

text

Comments.

schema

character varying(64)

Name of the namespace to which the column belongs.
Parent topic: Other System Views