Re: Report BUG: The column size for BIT VARYING(5) type is incorrect
| От | Jon Raiford |
|---|---|
| Тема | Re: Report BUG: The column size for BIT VARYING(5) type is incorrect |
| Дата | |
| Msg-id | OFAF7AB175.419F748F-ON852585D1.004F51A9-852585D1.0050D836@labware.com обсуждение исходный текст |
| Ответ на | Re: Report BUG: The column size for BIT VARYING(5) type is incorrect (Clemens Ladisch <clemens@ladisch.de>) |
| Список | pgsql-odbc |
"Clemens Ladisch" <clemens@ladisch.de> wrote on 08/26/2020 03:01:20 AM:
> > Why is the *ColumnSizePtr = 1 instead of *ColumnSizePtr = 5 since
> the column is created with bit varying (5) in the test case?
>
> The ODBC specification does not define the data type BIT VARYING, so the
> ODBC driver tries to represent it as a blob or text.
>
> And five bits fit into one byte.
I'm not sure this is the correct interpretation. According to PostgreSQL, bit varying(n) is a bit "string" (https://www.postgresql.org/docs/12/datatype-bit.html). The ODBC spec says that the column size for all string types is defined as the "... maximum column size in characters of the column or parameter" (https://docs.microsoft.com/en-us/sql/odbc/reference/appendixes/column-size). Also, according to the bug report, SQLDescribeCol answered that the data type in this case was returned as SQL_WVARRCHAR.
I don't use this type myself but based on the documentation and the (fact?) SQLDescribeCol answers the type as SQL_WVARCHAR, it does make sense to me for the column size to match the number of characters needed to represent the bits.
Jon
> > Why is the *ColumnSizePtr = 1 instead of *ColumnSizePtr = 5 since
> the column is created with bit varying (5) in the test case?
>
> The ODBC specification does not define the data type BIT VARYING, so the
> ODBC driver tries to represent it as a blob or text.
>
> And five bits fit into one byte.
I'm not sure this is the correct interpretation. According to PostgreSQL, bit varying(n) is a bit "string" (https://www.postgresql.org/docs/12/datatype-bit.html). The ODBC spec says that the column size for all string types is defined as the "... maximum column size in characters of the column or parameter" (https://docs.microsoft.com/en-us/sql/odbc/reference/appendixes/column-size). Also, according to the bug report, SQLDescribeCol answered that the data type in this case was returned as SQL_WVARRCHAR.
I don't use this type myself but based on the documentation and the (fact?) SQLDescribeCol answers the type as SQL_WVARCHAR, it does make sense to me for the column size to match the number of characters needed to represent the bits.
Jon
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