SQL_MORE_DATA - When is bound buffer filled?

[matthew-wozniczka]

In section 3.8 (Variable Length Columns) it states:

When the driver returns SQL_MORE_DATA, the application calls SQLNextColumn in order to determine the column of partially fetched data. The bound buffer will be populated and the str_len_or_ind_ptr will indicate the total amount of data available, if known, or SQL_NO_TOTAL if the driver does not know how much additional data is to be written.

Is the buffer populated after SQLFetch/SQLFetchScroll returns, or only after SQLNextColumn does? I would expect the former, but the text implies the latter (Only relevant since the application can determine which bindings were filled thanks to the new SQL_DATA_UNAVAILABLE).

[mikepizzo]

Contract is that the buffer is populated once SQLNextColumn is called. Driver could populate sooner, but client should not expect it to be populated when SQLNextColumn is called.

[matthew-wozniczka]

Related to #101

[mikepizzo]

Sorry; misread that this is the SQL_MORE_DATA state. At the time SQL_MORE_DATA is returned, the buffer should contain up to the first BufferLength number of characters, and str_len_or_ind_ptr should indicate the total amount of data available, if known. This is a hint to the application how much buffer to allocate in SqlGetData for the remaining data.

[mikepizzo]

Clarified in section 3.8: When the length of data exceeds the bound buffer for string or binary data, and the application has set SQL_ATTR_LENGTH_EXCEPTION_BEHAVIOR to SQL_LE_REPORT, the driver populates as much data as fits in the allocated buffer, sets str_len_or_ind_ptr to indicate the total amount of data available, if known, or SQL_NO_TOTAL if the driver does not know how much additional data is to be written, and returns SQL_MORE_DATA.