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. Its 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 non-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. Its 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 if the data type is varchar, nvarchar2, bpchar, or char, and to NULL for other data types.
v80_fmt_image	character varying(3)	Not supported. Its 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. Its value is NULL.
identity_column	character varying(3)	Not supported. Its value is NULL.
evaluation_edition	character varying(128)	Not supported. Its value is NULL.
unusable_before	character varying(128)	Not supported. Its value is NULL.
unusable_beginning	character varying(128)	Not supported. Its 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.