Data Type Identifiers and Descriptors
The data types listed in the SQL Data Types and C Data Types sections earlier in this appendix are "concise" data types: Each identifier refers to a single data type. There is a one-to-one correspondence between the identifier and the data type. Descriptors, however, do not in all cases use a single value to identify data types. In some cases, they use a "verbose" data type and a type subcode. For all data types except datetime and interval data types, the verbose type identifier is the same as the concise type identifier and the value in SQL_DESC_DATETIME_INTERVAL_CODE is equal to 0. For datetime and interval data types, however, a verbose type (SQL_DATETIME or SQL_INTERVAL) is stored in SQL_DESC_TYPE, a concise type is stored in SQL_DESC_CONCISE_TYPE, and a subcode for each concise type is stored in SQL_DESC_DATETIME_INTERVAL_CODE. Setting one of these fields affects the others. For more information about these fields, see the SQLSetDescField function description.
When the SQL_DESC_TYPE or SQL_DESC_CONCISE_TYPE field is set for some data types, the SQL_DESC_DATETIME_INTERVAL_PRECISION, SQL_DESC_LENGTH, SQL_DESC_PRECISION, and SQL_DESC_SCALE fields are automatically set to default values, as applicable for the data type. For more information, see the description of the SQL_DESC_TYPE field in SQLSetDescField. If any of the default values set is not appropriate, the application should explicitly set the descriptor field through a call to SQLSetDescField.
The following table shows the concise type identifier, verbose type identifier, and type subcode for each datetime and interval SQL and C type identifier. As this table indicates, for datetime and interval data types, the SQL_DESC_TYPE and SQL_DESC_DATETIME_INTERVAL_CODE fields have the same manifest constants both for SQL data types (in implementation descriptors) and for C data types (in application descriptors).
| Concise SQL type | Concise C type | Verbose type | DATETIME_INTERVAL_CODE |
|---|---|---|---|
| SQL_TYPE_DATE | SQL_C_TYPE_DATE | SQL_DATETIME | SQL_CODE_DATE |
| SQL_TYPE_TIME | SQL_C_TYPE_TIME | SQL_DATETIME | SQL_CODE_TIME |
| SQL_TYPE_TIMESTAMP | SQL_C_TYPE_TIMESTAMP | SQL_DATETIME | SQL_CODE_TIMESTAMP |
| SQL_INTERVAL_MONTH | SQL_C_INTERVAL_MONTH | SQL_INTERVAL | SQL_CODE_MONTH |
| SQL_INTERVAL_YEAR | SQL_C_INTERVAL_YEAR | SQL_INTERVAL | SQL_CODE_YEAR |
| SQL_INTERVAL_YEAR_TO_MONTH | SQL_C_INTERVAL_YEAR_TO_MONTH | SQL_INTERVAL | SQL_CODE_YEAR_TO_MONTH |
| SQL_INTERVAL_DAY | SQL_C_INTERVAL_DAY | SQL_INTERVAL | SQL_CODE_DAY |
| SQL_INTERVAL_HOUR | SQL_C_INTERVAL_HOUR | SQL_INTERVAL | SQL_CODE_HOUR |
| SQL_INTERVAL_MINUTE | SQL_C_INTERVAL_MINUTE | SQL_INTERVAL | SQL_CODE_MINUTE |
| SQL_INTERVAL_SECOND | SQL_C_INTERVAL_SECOND | SQL_INTERVAL | SQL_CODE_SECOND |
| SQL_INTERVAL_DAY_TO_HOUR | SQL_C_INTERVAL_DAY_TO_HOUR | SQL_INTERVAL | SQL_CODE_DAY_TO_HOUR |
| SQL_INTERVAL_DAY_TO_MINUTE | SQL_C_INTERVAL_DAY_TO_MINUTE | SQL_INTERVAL | SQL_CODE_DAY_TO_MINUTE |
| SQL_INTERVAL_DAY_TO_SECOND | SQL_C_INTERVAL_DAY_TO_SECOND | SQL_INTERVAL | SQL_CODE_DAY_TO_SECOND |
| SQL_INTERVAL_HOUR_TO_MINUTE | SQL_C_INTERVAL_HOUR_TO_MINUTE | SQL_INTERVAL | SQL_CODE_HOUR_TO_MINUTE |
| SQL_INTERVAL_HOUR_TO_SECOND | SQL_C_INTERVAL_HOUR_TO_SECOND | SQL_INTERVAL | SQL_CODE_HOUR_TO_SECOND |
| SQL_INTERVAL_MINUTE_TO_SECOND | SQL_C_INTERVAL_MINUTE_TO_SECOND | SQL_INTERVAL | SQL_CODE_MINUTE_TO_SECOND |