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The following SQL data types can be passed to an external library:
| SQL data type | C type |
|---|---|
| CHAR | Character data, with a specified length |
| VARCHAR | Character data, with a specified length |
| LONG VARCHAR | Character data, with a specified length |
| BINARY | Binary data, with a specified length |
| LONG BINARY | Character data, with a specified length |
| TINYINT | 1-byte integer |
| [ UNSIGNED ] SMALLINT | [ Unsigned ] 2-byte integer |
| [ UNSIGNED ] INT | [ Unsigned ] 4-byte integer |
| [ UNSIGNED ] BIGINT | [ Unsigned ] 8-byte integer |
| VARBINARY | Binary data, with a specified length |
| REAL | Single precision floating point number |
| DOUBLE | Double precision floating point number |
You cannot use date or time data types, and you cannot use exact numeric data types.
To provide values for INOUT or OUT parameters, use the set_value API function. To read IN and INOUT parameters, use the get_value API function.
You can pass NULL as a valid value for all arguments. Functions in external libraries can supply NULL as a return value for any data type.
To set a return value for an external function, call the set_value function with an arg_num parameter of 0. If set_value is not called with arg_num=0, the function result is NULL.