Data Types for Microsoft SQL Server :: SAS/ACCESS(R) 9.3 for Relational Databases: Reference, Second Edition

Overview

This section includes information about Microsoft SQL Server null and default values and data conversions.

Every column in a table has a name and a data type. The data type tells the Microsoft SQL Server how much physical storage to set aside for the column and the form in which the data is stored.

Microsoft SQL Server Null Values

Microsoft SQL Server has a special value called NULL. A Microsoft SQL Server NULL value means an absence of information and is analogous to a SAS missing value. When SAS/ACCESS reads a Microsoft SQL Server NULL value, it interprets it as a SAS missing value.

Microsoft SQL Server columns can be defined as NOT NULL so that they require data—they cannot contain NULL values. When a column is defined as NOT NULL, the DBMS does not add a row to the table unless the row has a value for that column. When creating a DBMS table with SAS/ACCESS, you can use the DBNULL= data set option to indicate whether NULL is a valid value for specified columns.

For more information about how SAS handles NULL values, see Potential Result Set Differences When Processing Null Data .

To control how SAS missing character values are handled, use the NULLCHAR= and NULLCHARVAL= data set options.

LIBNAME Statement Data Conversions

The following table shows all data types and default SAS formats that SAS/ACCESS Interface to Microsoft SQL Server supports.

Microsoft SQL Server Data Types and Default SAS Formats

Microsoft SQL Server Data Type	Default SAS Format
SQL_CHAR	$n
SQL_VARCHAR	$n
SQL_LONGVARCHAR	$n
SQL_BINARY	$n.1
SQL_VARBINARY	$n.1
SQL_LONGVARBINARY	$n.1
SQL_DECIMAL	m or m.n or none if m and n are not specified
SQL_NUMERIC	m or m.n or none if m and n are not specified
SQL_INTEGER	11.
SQL_SMALLINT	6.
SQL_TINYINT	4.
SQL_BIT	1.
SQL_REAL	none
SQL_FLOAT	none
SQL_DOUBLE	none
SQL_BIGINT	20.
SQL_DATE	DATE9.
SQL_TIME	TIME8. Microsoft SQL Server cannot support fractions of seconds for time values
SQL_TIMESTAMP	DATETIMEm.n where m and n depend on precision
1Because the Microsoft SQL Server driver does the conversion, this field is displayed as if the $HEXn. format were applied.

The following table shows the default data types that the Microsoft SQL Server interface uses when creating tables.

Default Microsoft SQL Server Output Data Types

SAS Variable Format	Default Microsoft SQL Server Data Type
m.n	SQL_DOUBLE or SQL_NUMERIC using m.n if the DBMS allows it
$n.	SQL_VARCHAR using n
datetime formats	SQL_TIMESTAMP
date formats	SQL_DATE
time formats	SQL_TIME

The Microsoft SQL Server interface allows non-default data types to be specified with the DBTYPE= data set option.