DBA_TAB_COLUMNS

Oracle 11gR1

DBA_TAB_COLUMNS describes the columns of all tables, views, and clusters in the database. Its columns are the same as those in "ALL_TAB_COLUMNS". To gather statistics for this view, use the SQL ANALYZE statement.

Related Views

· ALL_TAB_COLUMNS describes the columns of the tables, views, and clusters accessible to the current user. To gather statistics for this view, use the ANALYZE SQL statement or the DBMS_STATS package.

· USER_TAB_COLUMNS describes the columns of the 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	Name of the table, view, or cluster
COLUMN_NAME	VARCHAR2(30)	NOT NULL	Column name
DATA_TYPE	VARCHAR2(106)		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. The constraint should be in an ENABLE VALIDATE state.
COLUMN_ID	NUMBER		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		Number of distinct values in the column The column remains for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views.
LOW_VALUE	RAW(32)		Low value in the column The column remains for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views.
HIGH_VALUE	RAW(32)		High value in the column The column remains for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views.
DENSITY	NUMBER		Density of the column The column remains for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views.
NUM_NULLS	NUMBER		Number of nulls in the column
NUM_BUCKETS	NUMBER		Number of buckets in the histogram for the column Note: The number of buckets in a histogram is specified in the SIZE parameter of the SQL statement ANALYZE. However, the Oracle Database does not create a histogram with more buckets than the number of rows in the sample. Also, if the sample contains any values that are very repetitious, the Oracle Database creates the specified number of buckets, but the value indicated by this column may be smaller because of an internal compression algorithm.
LAST_ANALYZED	DATE		Date on which this column was most recently analyzed
SAMPLE_SIZE	NUMBER		Sample size used in analyzing this column
CHARACTER_SET_NAME	VARCHAR2(44)		Name of the character set: CHAR_CS or NCHAR_CS
CHAR_COL_DECL_LENGTH	NUMBER		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)		Indicates whether statistics were entered directly by the user (YES) or not (NO)
AVG_COL_LEN	NUMBER		Average length of the column (in bytes)
CHAR_LENGTH	NUMBER		Displays the length of the column in characters. This value only applies to the following datatypes: · CHAR · VARCHAR2 · NCHAR · NVARCHAR
CHAR_USED	VARCHAR2(1)		B | C. B indicates that the column uses BYTE length semantics. C indicates that the column uses CHAR length semantics. NULL indicates the datatype is not any of the following: · CHAR · VARCHAR2 · NCHAR · NVARCHAR2
V80_FMT_IMAGE	VARCHAR2(3)		Indicates whether the column data is in release 8.0 image format (YES) or not (NO)
DATA_UPGRADED	VARCHAR2(3)		Indicates whether the column data has been upgraded to the latest type version format (YES) or not (NO)
HISTOGRAM	VARCHAR2(15)		Indicates existence/type of histogram: · NONE · FREQUENCY · HEIGHT BALANCED

Note:

1.

select owner, table_name, column_name, data_type, data_length, nullable, last_analyzed, character_set_name, global_stats, data_upgraded, histogram

from dba_tab_columns

where data_type in ('NCHAR', 'NCLOB', 'NVARCHAR2');

OWNER	TABLE_ NAME	COLUMN_ NAME	DATA_ TYPE	DATA_ LENGTH	NULLABLE	LAST_ ANALYZED	CHARACTER_ SET_ NAME	GLOBAL_ STATS	DATA_ UPGRADED	HISTOGRAM
XDB	XDB$NMSPC_ID	NMSPCURI	NVARCHAR2	4000	Y	2008-07-31 2:33:00 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_AUDIT_STATEMENT	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
XDB	XDB$QNAME_ID	LOCALNAME	NVARCHAR2	4000	Y	2008-07-31 2:33:01 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_AUDIT_TRAIL	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_REPPRIORITY	NCHAR_VALUE	NCHAR	1000	Y		NCHAR_CS	NO	YES	NONE
SYS	USER_REPPRIORITY	NVARCHAR2_VALUE	NVARCHAR2	2000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_FGA_AUDIT_TRAIL	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_FGA_AUDIT_TRAIL	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	STREAMS$_DEF_PROC	NCLOB_VALUE	NCLOB	4000	Y	2008-07-31 2:21:56 PM	NCHAR_CS	YES	YES	NONE
SYS	ALL_REPPRIORITY	NCHAR_VALUE	NCHAR	1000	Y		NCHAR_CS	NO	YES	NONE
SDE	SDE_XML_INDEX_TAGS	TAG_NAME	NVARCHAR2	2048	N	2008-08-05 10:00:49 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_AUDIT_OBJECT	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	USER_AUDIT_OBJECT	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_COMMON_AUDIT_TRAIL	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYSTEM	DEF$_LOB	NCLOB_COL	NCLOB	4000	Y	2008-07-31 2:21:18 PM	NCHAR_CS	YES	YES	NONE
SYSTEM	REPCAT$_PRIORITY	NVARCHAR2_VALUE	NVARCHAR2	2000	Y	2008-07-31 2:21:23 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_AUDIT_STATEMENT	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DEFLOB	NCLOB_COL	NCLOB	4000	Y		NCHAR_CS	NO	YES	NONE
SYSTEM	DEF$_TEMP$LOB	TEMP$NCLOB	NCLOB	4000	Y	2008-07-31 2:21:18 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_AUDIT_TRAIL	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_STATEMENT	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_OBJECT	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_REPPRIORITY	NVARCHAR2_VALUE	NVARCHAR2	2000	Y		NCHAR_CS	NO	YES	NONE
SYS	STREAMS$_DEF_PROC	NVARCHAR2_VALUE	NVARCHAR2	2000	Y	2008-07-31 2:21:56 PM	NCHAR_CS	YES	YES	NONE
SYS	USER_REPPRIORITY	NCHAR_VALUE	NCHAR	1000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_COMMON_AUDIT_TRAIL	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_OBJECT	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYSTEM	REPCAT$_PRIORITY	NCHAR_VALUE	NCHAR	1000	Y	2008-07-31 2:21:23 PM	NCHAR_CS	YES	YES	NONE
SYS	DBA_AUDIT_TRAIL	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
XDB	XDB$DXPATH	XPATH	NVARCHAR2	4000	N	2008-07-31 2:33:00 PM	NCHAR_CS	YES	YES	NONE
SYS	DBA_AUDIT_STATEMENT	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_TRAIL	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_EXISTS	SQL_BIND	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	DBA_AUDIT_EXISTS	SQL_TEXT	NVARCHAR2	4000	Y		NCHAR_CS	NO	YES	NONE
SYS	ALL_REPPRIORITY	NVARCHAR2_VALUE	NVARCHAR2	2000	Y		NCHAR_CS	NO	YES	NONE

Oracle data dictionary views