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 | Scripting Name | Description |
|---|---|---|
| Index | WhereNotNull | 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. |
| Lob option | ExtLobOption | Specifies options for LOB data type columns. |
| For bit data | ExtForBitData | 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. |
| Expression | ExtGenExpr | Specifies that the definition of the column is based on an expression. |
| Always Generate value | ExtGenAlways | 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. |
| Field procedure name | ExtFieldProcName | Defines the procedure that will be used as generator/cryptor of values. |
| Character subtype | ExtData | 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. |
| Generated value | ExtGeneratedAs | 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. |
| Character subtype | ExtSubtypeData | Specifies a subtype for a character string column. |
The following extended attributes are available on the DB2 tab:
| Name | Scripting Name | Description |
|---|---|---|
| Character Subtype | ExtSubtypeData | Specifies a subtype for a character string column. |
The following extended attributes are available on the Extended Attributes tab:
| Name | Scripting Name | Description |
|---|---|---|
| [none] | WhereNotNull | 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. |
The following extended attributes are available on the DB2 tab:
| Name | Scripting Name | Description |
|---|---|---|
| Table | ExtTablePctFree | Indicates what percentage of each tab to leave as free space during load or reorganization. |
The following extended attributes are available on the Extended Attributes tab:
| Name | Scripting Name | Description |
|---|---|---|
| [none] | ExtTablespaceType | Specifies the tablespace type, as defined in the extended attribute type ExtTablespaceTypeList. |
| [none] | TbspDatabase | Specifies the database that owns the tablespace. |
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