Solution Guide for Migrating Oracle on UNIX to SQL Server - Willy .Net

<strong>Solution</strong> <strong>Guide</strong> <strong>for</strong> <strong>Migrating</strong> <strong>Oracle</strong> on UNIX to SQL Server on Windows 115 To create a UNIQUE constraint using T-SQL, use the following syntax:The only syntactic difference in the UNIQUE constraint definition between <strong>Oracle</strong> andSQL Server is with the USING INDEX clause used to define the index that en<strong>for</strong>ces theconstraint. The USING INDEX clause of <strong>Oracle</strong> has an equivalent in SQL Server and canbe used with both column and table constraints. The syntax <strong>for</strong> table constraint isdescribed in Table 6.14.Table 6.14: SQL Statements <strong>for</strong> Defining UNIQUE Constraints in <strong>Oracle</strong> andSQL Server<strong>Oracle</strong>SQL ServerCREATE TABLE table_nameCREATE TABLE table_name((column_name datatype,column_name datatype,…,…,[ CONSTRAINT constraint_name ] [ CONSTRAINT constraint_name ]UNIQUE ( column_name [, …] ) UNIQUE [ CLUSTERED | NONCLUSTERED ][ USING INDEX [ TABLESPACE( column_name [, …] )tablespace_name ][ WITH FILLFACTOR = fillfactor ][ storage_definition ] ][ ON FILEGROUP { filegroup |DEFAULT } ]Primary Key ConstraintPRIMARY KEY constraints have all the characteristics of UNIQUE constraints, with theadditional restriction that all primary key columns be NOT NULL. <strong>Oracle</strong> creates aUNIQUE index and a NOT NULL constraint to implement PRIMARY KEY constraints.With <strong>Oracle</strong> 9i, an existing non-unique index may be used to en<strong>for</strong>ce the primary keyconstraint. In SQL Server, if a clustered index does not already exist on the table, or anonclustered index is not explicitly specified, a unique, clustered index is created toen<strong>for</strong>ce the PRIMARY KEY constraint. The following procedures demonstrate that it is fareasier to use T-SQL than Enterprise Manager when it comes to creating a PRIMARYKEY constraint. To create a primary key constraint using Enterprise Manager, follow thesesteps:1. In the Table Designer, click and select the colum n(s) that are part of the primarykey (use the Ctrl key <strong>for</strong> this).2. Right-clic k anywhere along the selected column(s) and click Set Primary Key. Acheck mark appears next to the Set Primary Key option.3. A unique clustered in dex using the naming convention PK_table_name isautomatically created by the system.4. The name and properties of the index can be changed from those assigned by thesystem through the Indexes/Keys pane of the Table and Index Propertieswindow. To create a primary key constraint using T-SQL, use the following syntax:<strong>Oracle</strong> and SQL Server differ only in the USING INDEX part of the PRIMARY KEYconstraint syntax. The syntax differs from the UNIQUE constraint definition only in theUNIQUE keyword being replaced with PRIMARY KEY. In both <strong>Oracle</strong> and SQL Server, aNOT NULL constraint is added by the system <strong>for</strong> all primary key columns when one is notexplicitlyspecified.