Information is shown for the following data type attributes:
Precision
The precision of a numeric column or parameter refers to the maximum number
of digits used by the data type of the column or parameter. The
precision of a non-numeric column or parameter generally refers to the maximum
length or the defined length of the column or parameter. The following
table defines the precision for each SQL data type.
| fSqlType | Precision |
|---|---|
|
SQL_CHAR SQL_VARCHAR | The defined length of the column or parameter. For example, the precision of a column defined as CHAR(10) is 10. |
| SQL_DECIMAL | The defined maximum number of digits. For example, the precision of a column defined as DECIMAL(10,3) is 10. |
| SQL_SMALLINT a | 5 |
| SQL_INTEGER a | 10 |
| SQL_BLOB | The defined length of the column or parameter. For example, the precision of a column defined as BLOB(10), is 10. |
| SQL_DATE a | 10 (the number of characters in the yyyy-mm-dd format). |
| SQL_TIME a | 8 (the number of characters in the hh:mm:ss format). |
| SQL_TIMESTAMP | 26 (The number of characters in the "yyyy-mm-dd-hh.mm.ss.ffffff" format used by the TIMESTAMP data type.) |
a: The cbParamDef argument of SQLBindParameter() is ignored for this data type.
Scale
The scale of a numeric column or parameter refers to the maximum number of
digits to the right of the decimal point. The following table defines
the scale for each SQL data type.
| fSqlType | Scale |
|---|---|
|
SQL_CHAR SQL_VARCHAR | Not applicable. |
| SQL_DECIMAL | The defined number of digits to the right of the decimal place. For example, the scale of a column defined as DECIMAL(10, 3) is 3. |
|
SQL_SMALLINT SQL_INTEGER | 0 |
| SQL_BLOB | Not applicable. |
|
SQL_DATE SQL_TIME | Not applicable. |
| SQL_TIMESTAMP | 6 (The number of digits to the right of the decimal point in the "yyyy-mm-dd-hh.mm.ss.ffffff" format.) |
Length
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.
The following table defines the length for each SQL data type.
| fSqlType | Length |
|---|---|
|
SQL_CHAR SQL_VARCHAR | The defined length of the column. For example, the length of a column defined as CHAR(10) is 10. |
| SQL_DECIMAL | 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 DECIMAL(10,3) is 12. |
| SQL_SMALLINT | 2 (two bytes). |
| SQL_INTEGER | 4 (four bytes). |
| SQL_BLOB | The defined length of the column. For example, the length of a column defined as BLOB(10) is 10. |
|
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). |
Display size
The display size of a column is the maximum number of bytes needed to
display data in character form. The following table defines the display
size for each SQL data type.
| fSqlType | Display size |
|---|---|
|
SQL_CHAR SQL_VARCHAR | The defined length of the column. For example, the display size of a column defined as CHAR(10) is 10. |
| SQL_DECIMAL | The precision of the column plus two (a sign, precision digits, and a decimal point). For example, the display size of a column defined as DECIMAL(10,3) is 12. |
| SQL_SMALLINT | 6 (a sign and 5 digits). |
| SQL_INTEGER | 11 (a sign and 10 digits). |
| SQL_BLOB | The defined length of the column times 2 (each binary byte is represented by a 2 digit hexadecimal number). For example, the display size of a column defined as BLOB(10) is 20. |
| SQL_DATE | 10 (a date in the format yyyy-mm-dd). |
| SQL_TIME | 8 (a time in the format hh:mm:ss). |
| SQL_TIMESTAMP | 26 (a timestamp in the format yyyy-mm-dd-hh.mm.ss.ffffff). |