ALL_TAB_COLS 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.

This view differs from "ALL_TAB_COLUMNS" in that hidden columns are not filtered out.

Related Views

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

  • USER_TAB_COLS 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
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.
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 columnFoot 1 
LOW_VALUE RAW(32)   Low value in the columnFootref 1
HIGH_VALUE RAW(32)   High value in the columnFootref 1
DENSITY NUMBER   Density of the columnFootref 1
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
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




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




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)
HIDDEN_COLUMN VARCHAR2(3)   Indicates whether the column is a hidden column (YES) or not (NO)
VIRTUAL_COLUMN VARCHAR2(3)   Indicates whether the column is a virtual column (YES) or not (NO)
SEGMENT_COLUMN_ID NUMBER   Sequence number of the column in the segment
INTERNAL_COLUMN_ID NUMBER NOT NULL Internal sequence number of the column
HISTOGRAM VARCHAR2(15)   Indicates existence/type of histogram:
  • NONE



QUALIFIED_COL_NAME VARCHAR2(4000)   Qualified column name

Footnote 1 These columns remain for backward compatibility with Oracle7. This information is now in the {TAB|PART}_COL_STATISTICS views.