Chapter 15 DBMS-Specific Features
The following extended attributes are defined by default in the IBM DB 2 Logical DBMS.
The following extended attributes are available on the DB2 tab. The list will vary depending on the database version and whether you are working with Common Server or OS/390:
| Name | Description |
|---|---|
| Index | Specifies that the uniqueness constraint does not apply to the key value if any column of the key is null. This applies when the index is a primary key.
Scripting name: WhereNotNull |
| Lob option | Specifies options for LOB data type columns.
Scripting name: ExtLobOption |
| For bit data | Specifies that the content of the column is to be treated as bit (binary) data. This is only applicable on columns with a character datatype.
Scripting name: ExtForBitData |
| Expression | Specifies that the definition of the column is based on an expression.
Scripting name: ExtGenExpr |
| Always Generate value | When set to True (generated always), indicates that DB2 will always generate a value for the column when a row is inserted into the table or whenever the result value of the generation-expression may change.
When set to False (generated by default), indicates that DB2 will generate a value for the column when a row is inserted into the table, unless a value is specified. Scripting name: ExtGenAlways |
| Field procedure name | Defines the procedure that will be used as generator/cryptor of values.
Scripting name: ExtFieldProcName |
| Character subtype | Specifies a subtype for a character string column (column with a CHAR,VARCHAR,or LONG VARCHAR data type). The subtype can proceed from the list defined in extended attribute type T_ForData.
Scripting name: ExtData |
| Generated value | Indicates that DB2 generates values for the column using the computed column function. If you select Always, the server will send an error message if you try to type a value in the column. If you select By Default, the server uses the computed column value or the value typed for the column.
Scripting name: ExtGeneratedAs |
| Character subtype | Specifies a subtype for a character string column.
Scripting name: ExtSubtypeData |
The following extended attributes are available on the DB2 tab:
| Name | Description |
|---|---|
| Character Subtype | Specifies a subtype for a character string column.
Scripting name: ExtSubtypeData |
The following extended attributes are available on the Extended Attributes tab:
| Name | Description |
|---|---|
| [none] | Specifies that the uniqueness constraint does not apply to the key value if any column of the key is null. This applies when the index is a primary key.
Scripting name: WhereNotNull |
The following extended attributes are available on the DB2 tab:
| Name | Description |
|---|---|
| Table | Indicates what percentage of each tab to leave as free space during load or reorganization.
Scripting name: ExtTablePctFree |
The following extended attributes are available on the Extended Attributes tab:
| Name | Description |
|---|---|
| [none] | Specifies the tablespace type, as defined in the extended attribute type ExtTablespaceTypeList.
Scripting name: ExtTablespaceType |
| [none] | Specifies the database that owns the tablespace.
Scripting name: TbspDatabase |
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