MDAC 2.5 SDK - ODBC Programmer's Reference
Appendix D: Data Types
The identifiers for the character ODBC C data type are:
SQL_C_CHAR
SQL_C_WCHAR
The following table shows the ODBC SQL data types to which C character data may be converted. For an explanation of the columns and terms in the table, see "Converting Data from C to SQL Data Types."
Note When character C data is converted to Unicode SQL data, the length of the Unicode data must be an even number.
| SQL type identifier | Test | SQLSTATE |
| SQL_CHAR SQL_VARCHAR SQL_LONGVARCHAR |
Byte length of data <= Column length.
Byte length of data > Column length. |
n/a 22001 |
| SQL_WCHAR SQL_WVARCHAR SQL_WLONGVARCHAR |
Character length of data <= Column length.
Character length of data > Column length. |
n/a 22001 |
| SQL_DECIMAL SQL_NUMERIC SQL_TINYINT SQL_SMALLINT SQL_INTEGER SQL_BIGINT |
Data converted without truncation
Data converted with truncation of fractional digits[e] Conversion of data would result in loss of whole (as opposed to fractional) digits[e] Data value is not a numeric-literal |
n/a
22001 22001 22018 |
| SQL_REAL SQL_FLOAT SQL_DOUBLE |
Data is within the range of the data type to which the number is being converted
Data is outside the range of the data type to which the number is being converted Data value is not a numeric-literal |
n/a 22003 22018 |
| SQL_BIT | Data is 0 or 1
Data is greater than 0, less than 2, and not equal to 1 Data is less than 0 or greater than or equal to 2 Data is not a numeric-literal |
n/a
22001 22003 22018 |
| SQL_BINARY SQL_VARBINARY SQL_LONGVARBINARY |
(Byte length of data) / 2 <= column byte length
(Byte length of data) / 2 > column byte length Data value is not a hexadecimal value |
n/a 22001 22018 |
| SQL_TYPE_DATE | Data value is a valid ODBC-date-literal
Data value is a valid ODBC-timestamp-literal; time portion is zero Data value is a valid ODBC-timestamp-literal; time portion is nonzero[a] Data value is not a valid ODBC-date-literal or ODBC-timestamp-literal |
n/a n/a 22008 22018 |
| SQL_TYPE_TIME | Data value is a valid ODBC-time-literal
Data value is a valid ODBC-timestamp-literal; fractional seconds portion is zero[b] Data value is a valid ODBC-timestamp-literal; fractional seconds portion is nonzero[b] Data value is not a valid ODBC-time-literal or ODBC-timestamp-literal |
n/a n/a 22008 22018 |
| SQL_TYPE_TIMESTAMP | Data value is a valid ODBC- timestamp-literal; fractional seconds portion not truncated Data value is a valid ODBC-timestamp-literal; fractional seconds portion truncated Data value is a valid ODBC-date-literal[c] Data value is a valid ODBC-time-literal[d] Data value is not a valid ODBC-date-literal, ODBC-time-literal, or ODBC-timestamp-literal |
n/a 22008 n/a n/a 22018 |
| All SQL interval types | Data value is a valid interval value; no truncation occurs
Data value is a valid interval value; the value in one of the fields is truncated The data value is not a valid interval literal |
n/a 22015 22018 |
[a] The time portion of the timestamp is truncated.
[b] The date portion of the timestamp is ignored.
[c] The time portion of the timestamp is set to zero.
[d] The date portion of the timestamp is set to the current date.
[e] The driver/data source effectively waits until the entire string has been received (even if the character data is sent in pieces by calls to SQLPutData) before attempting to perform the conversion.
When character C data is converted to numeric, date, time, or timestamp SQL data, leading and trailing blanks are ignored.
When character C data is converted to binary SQL data, each two bytes of character data are converted to a single byte (8 bits) of binary data. Each two bytes of character data represent a number in hexadecimal form. For example, "01" is converted to a binary 00000001 and "FF" is converted to a binary 11111111.
The driver always converts pairs of hexadecimal digits to individual bytes and ignores the null-termination byte. Because of this, if the length of the character string is odd, the last byte of the string (excluding the null-termination byte, if any) is not converted.
Note Application developers are discouraged from binding character C data to a binary SQL data type. This conversion is usually inefficient and slow.