The length of a column is the maximum number of bytes returned to the application when data is transferred to its default C data type. For character data, the length does not include the null termination byte. Note that the length of a column may be different than the number of bytes required to store the data on the data source. For a list of default C data types, see the "Default C Data Types" section.
The following table defines the length for each SQL data type.
fSqlType |
Length |
|---|---|
SQL_CHAR SQL_VARCHAR SQL_CLOB | The defined length of the column. For example, the length of a column defined as CHAR(10) is 10. |
SQL_LONGVARCHAR |
The maximum length of the column. |
SQL_DECIMAL SQL_NUMERIC | The maximum number of digits plus two. Since these data types are returned as character strings, characters are needed for the digits, a sign, and a decimal point. For example, the length of a column defined as NUMERIC(10,3) is 12. |
SQL_SMALLINT | 2 (two bytes). |
| SQL_INTEGER |
4 (four bytes). |
SQL_REAL |
4 (four bytes). |
SQL_FLOAT |
8 (eight bytes). |
SQL_DOUBLE |
8 (eight bytes). |
SQL_BINARY SQL_VARBINARY SQL_BLOB | The defined length of the column. For example, the length of a column defined as CHAR(10) FOR BIT DATA is 10. |
SQL_LONGVARBINARY | The maximum length of the column. |
SQL_DATE SQL_TIME | 6 (the size of the DATE_STRUCT or TIME_STRUCT structure). |
SQL_TIMESTAMP | 16 (the size of the TIMESTAMP_STRUCT structure). |
SQL_GRAPHIC SQL_VARGRAPHIC SQL_DBCLOB | The defined length of the column times 2. For example, the length of a column defined as GRAPHIC(10) is 20. |
SQL_LONGVARGRAPHIC | The maximum length of the column times 2. |