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 on 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 for both SQL data types (in implementation descriptors) and C data types (in application descriptors).

Concise SQL type

Concise C type

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