SQLDA - Content of SQLLEN

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The sqllen field of the sqlvar contains different values based on the

sqltype of the column.

For all datatypes except DECIMAL and NUMERIC the value contained in

sqllen is the actual length of the column.

The sqllen for DECIMAL and NUMERIC types, contains the length, precision

(identical to length) and scale. This can be decoded into length,

precision and scale variables by using the macro SQLDAGET_PREC_SCALE_LEN.

The sqllen can be encoded with length, precision and scale by using the

macro SQLDAPUT_PREC_SCALE_LEN.

The following SQLTYPES require decoding or encoding of the sqllen :

  SQL_TYP_DECIMAL

  SQL_TYP_NUMERIC

  SQL_TYP_NUMERIC_LD

  SQL_TYP_NUMERIC_TR

  SQL_TYP_NUMERIC_SLD

  SQL_TYP_NUMERIC_STR

  SQL_TYP_NUMERIC_BINARY

  SQL_TYP_NUMERIC_BIN_BE

  SQL_TYP_NDECIMAL

  SQL_TYP_NNUMERIC

  SQL_TYP_NNUMERIC_LD

  SQL_TYP_NNUMERIC_TR

  SQL_TYP_NNUMERIC_SLD

  SQL_TYP_NNUMERIC_STR

  SQL_TYP_NNUMERIC_BINARY

  SQL_TYP_NNUMERIC_BIN_BE

The sqllen field in the sqlvar should remain encoded and not be modified

therefore, if the length of the column is required, when allocating

storage for example, the decoded values sqlprec or sqllength should be

used and not the sqllen itself.

SAMPLE USAGE:

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/*

  Show how to decode sqllen for DECIMAL and NUMERIC type columns

  The SQLDAGET_PREC_SCALE_LEN and SQLDAPUT_PREC_SCALE_LEN macros are

  generated automatically by the Precompiler.

*/

  int   sqlprec;   /* Precision */

  int   sqlscale;  /* Scale     */

  int   sqllength; /* Length    */

  if ( Sqlda->sqlvar[n].sqltype == SQL_TYP_NDECIMAL

                                || SQL_TYP_NNUMERIC

                                || SQL_TYP_NNUMERIC_LD

                                || SQL_TYP_NNUMERIC_TR

                                || SQL_TYP_NNUMERIC_SLD

                                || SQL_TYP_NNUMERIC_STR

                                || SQL_TYP_NNUMERIC_BINARY

                                || SQL_TYP_NNUMERIC_BIN_BE)

  {

    SQLDAGET_PREC_SCALE_LEN(Sqlda->sqlvar[n].sqllen,

                            sqlprec,

                            sqlscale,

                            sqllength);

  }

/*

  Allocate storage using sqllength

*/

  Sqlda->sqlvar[n].sqldata.host_address = calloc(1, sqllength);