SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

602 Data Types for Microsoft SQL Server 4 Chapter 20Server; NO for all others. For additional information about these options, see “Overviewof the LIBNAME Statement for Relational Databases” on page 87.Microsoft SQL Server supports table names and column names that contain up to 32characters. If DBMS column names are longer than 32 characters, SAS truncates themto 32 characters. If truncating a column name would result in identical names, SASgenerates a unique name by replacing the last character with a number. DBMS tablenames must be 32 characters or less because SAS does not truncate a longer name. Ifyou already have a table name that is greater than 32 characters, it is recommendedthat you create a table view.Data Types for Microsoft SQL ServerOverviewEvery column in a table has a name and a data type. The data type tells theMicrosoft SQL Server how much physical storage to set aside for the column and theform in which the data is stored.Microsoft SQL Server Null ValuesMicrosoft SQL Server has a special value called NULL. A Microsoft SQL ServerNULL 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 aSAS missing value.Microsoft SQL Server columns can be defined as NOT NULL so that they requiredata—they cannot contain NULL values. When a column is defined as NOT NULL, theDBMS 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 setoption to indicate whether NULL is a valid value for specified columns.For more information about how SAS handles NULL values, see “Potential ResultSet Differences When Processing Null Data” on page 31 in SAS/ACCESS for RelationalDatabases: Reference.To control how SAS missing character values are handled by Microsoft SQL Server,use the NULLCHAR= and NULLCHARVAL= data set options.LIBNAME Statement Data ConversionsThe following table shows all data types and default SAS formats that SAS/ACCESSInterface to Microsoft SQL Server supports.Table 20.4Microsoft SQL Server Data Types and Default SAS FormatsMicrosoft SQL Server Data TypeDefault SAS FormatSQL_CHAR $nSQL_VARCHAR $nSQL_LONGVARCHAR $n