SQLDA field descriptions
An SQLDA consists of four variables, a header, and an arbitrary number of occurrences of a sequence of variables collectively named SQLVAR.
In DESCRIBE and PREPARE INTO, each occurrence of the SQLVAR describes the column of a table. In FETCH, OPEN, EXECUTE, and CALL, each occurrence describes a host variable.
The order of the SQLVAR entries matches the order of the columns in the table or the order of the parameter markers in the SQL statement.