Purpose
The oceanbase.CDB_TAB_COLS_V$ view provides the column information of the table and view objects in all tenants.
Note
This view is introduced since OceanBase Database V4.0.0.
Columns
| Column | Type | Nullable? | Description |
|---|---|---|---|
| CON_ID | bigint(20) | NO | The ID of the tenant. |
| OWNER | varchar(128) | NO | The owner of a table, view, or cluster. |
| TABLE_NAME | varchar(128) | NO | The name of a table, view, or cluster. |
| COLUMN_NAME | varchar(128) | NO | The name of the column. |
| DATA_TYPE | varchar(128) | NO | The data type of the column. |
| DATA_TYPE_MOD | varchar(3) | NO | The data type modifier of the column. |
| DATA_TYPE_OWNER | varchar(128) | NO | The owner of the column data type. |
| DATA_LENGTH | BIGINT(21) | NO | The column length, in bytes. |
| DATA_PRECISION | bigint(20) | NO | The decimal precision for the NUMBER data type and the binary precision for the FLOAT data type. The value is NULL for all other data types. |
| DATA_SCALE | bigint(20) | NO | The number of digits on the right of the decimal point in a number. |
| NULLABLE | varchar(1) | NO | Indicates whether null values are allowed for the column. The value indicates whether the column has NOT NULL constraints or whether the column belongs to the PRIMARY KEY. |
| COLUMN_ID | bigint(20) | NO | The serial number of the created column. |
| DEFAULT_LENGTH | bigint(20) | NO | The length of the default value for the column. |
| DATA_DEFAULT | mediumtext | NO | The default value of the column. |
| NUM_DISTINCT | bigint(20) | NO | The number of distinct values in the column. |
| LOW_VALUE | varchar(128) | NO | The low value in the column. |
| HIGH_VALUE | varchar(128) | NO | The high value in the column. |
| DENSITY | BIGINT(21) | NO | If you can create a histogram on the COLUMN_NAME column, this column shows the selectivity of the values with zero or one occurrence in the histogram. It does not represent the selectivity of values with two or more occurrences. If COLUMN_NAME is not available on the histogram, the value of this column is 1 or NUM_DISTINCT. |
| NUM_NULLS | bigint(20) | NO | The number of NULLs in the column. |
| NUM_BUCKETS | bigint(20) | NO | The number of buckets in the histogram of the column. |
| LAST_ANALYZED | date | NO | The date on which the column was last analyzed. |
| SAMPLE_SIZE | bigint(20) | NO | The sample size used to analyze the column. |
| CHARACTER_SET_NAME | varchar(44) | NO | The name of the character set. CHAR_CSNCHAR_CS |
| CHAR_COL_DECL_LENGTH | bigint(0) | NO | The declared length of the column of the character type. |
| GLOBAL_STATS | varchar(3) | NO | Indicates whether statistics are collected or incrementally maintained. Valid values: YES and NO. |
| USER_STATS | varchar(3) | NO | Indicates whether the statistics are directly entered by the user. Valid values: YES and NO. |
| NOTES | varchar(80) | NO | Some additional attributes. |
| AVG_COL_LEN | BIGINT(21) | NO | The average column length, in bytes. |
| CHAR_LENGTH | bigint(20) | NO | The column length in characters. The value applies only to the following data types: CHARVARCHAR2NCHARNVARCHAR2 |
| CHAR_USED | varchar(1) | NO | Indicates whether the column uses BYTE length semantics (value B) or CHAR length semantics (value C), or whether the data type is none of the following (value NULL): CHARVARCHAR2NCHARNVARCHAR2 |
| V80_FMT_IMAGE | varchar(3) | NO | Indicates whether the column data is in V8.0 image format. Valid values: YES and NO. |
| DATA_UPGRADED | varchar(3) | NO | Indicates whether column data has been upgraded to the latest type version format (YES) or not upgraded (NO) |
| HIDDEN_COLUMN | varchar(3) | NO | Indicates whether the column is a hidden one. Valid values: YES and NO. |
| VIRTUAL_COLUMN | varchar(3) | NO | Indicates whether the column is a virtual one. Valid values: YES and NO. |
| SEGMENT_COLUMN_ID | bigint(0) | NO | The sequence number of the column in the segment. |
| INTERNAL_COLUMN_ID | bigint(0) | NO | The internal serial number of the column. |
| HISTOGRAM | varchar(15) | NO | The existence and type of the histogram. Valid values: NONEFREQUENCYTOP-FREQUENCYHEIGHT BALANCEDHYBRID |
| QUALIFIED_COL_NAME | text | NO | The qualified column name. |
| USER_GENERATED | varchar(3) | NO | Indicates whether the column is a user-generated column (value YES) or a system-generated column (value NO). |
| DEFAULT_ON_NULL | varchar(3) | NO | Indicates whether the column has DEFAULT ON NULL semantics. Valid values: YES and NO. |
| IDENTITY_COLUMN | varchar(3) | NO | Indicates whether the column is an identifier column. Valid values: YES and NO. |
| EVALUATION_EDITION | varchar(128) | NO | The version of the edit object referenced in the Parse expression column. |
| UNUSABLE_BEFORE | varchar(128) | NO | The oldest version of the index that can be used as part of a query plan. |
| UNUSABLE_BEGINNING | varchar(128) | NO | The most recent version of the index that is not allowed to be used as part of a query plan. |
| COLLATION | varchar(100) | NO | The rule for sorting the column. It applies only to columns of character data types. |
| COLLATED_COLUMN_ID | bigint(0) | NO | The internal serial number of the column. This virtual column generates a collation key for the column. |
