This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
integration:rdbms:sqlserver:constraints [2011/04/07 22:14] doc |
integration:rdbms:sqlserver:constraints [2016/06/28 22:38] (current) |
||
|---|---|---|---|
| Line 25: | Line 25: | ||
| === Declaring Constraints === | === Declaring Constraints === | ||
| - | The table declarations in the Omnidex Environment File should include primary and foreign key constraints that establish parent-child relationships between the tables. While Omnidex does not validate or enforce these constraints; they are heavily used when optimizing queries. Omnidex does not need to know about column constraints that exist in SQL Server, such as NULL, NOT NULL, CHECK or DEFAULT constraints. | + | The table declarations in the Omnidex Environment File should include primary and foreign key constraints that establish parent-child relationships between the tables. While Omnidex does not validate or enforce these constraints; they are heavily used when optimizing queries. Omnidex does not need to know about column constraints that exist in SQL Server, such as NULL, NOT NULL, CHECK, or DEFAULT constraints. |
| In most situations, the constraints declared in Omnidex should match those declared in the SQL Server database; however, administrators may alter these if they wish. At times, a parent-child relationship may exist between tables in SQL Server even though a constraint is not formally declared. These can be declared in Omnidex, allowing more advanced optimization of multi-table queries. | In most situations, the constraints declared in Omnidex should match those declared in the SQL Server database; however, administrators may alter these if they wish. At times, a parent-child relationship may exist between tables in SQL Server even though a constraint is not formally declared. These can be declared in Omnidex, allowing more advanced optimization of multi-table queries. | ||
| Line 71: | Line 71: | ||
| === Declaring Indexes === | === Declaring Indexes === | ||
| - | SQL Server indexes that exist on primary and foreign key constraints should be declared as NATIVE indexes in the Omnidex Environment File. It can also be beneficial to declare other SQL Server indexes as well. | + | SQL Server indexes that exist on primary and foreign key constraints should be declared as NATIVE indexes in the Omnidex Environment File. It can be beneficial to declare other SQL Server indexes as well. |
| The Omnidex SQL Engine will evaluate the presence of native SQL Server indexes when deciding how to process a statement. At times, it may be faster to rely on the native SQL Server indexes than to use Omnidex indexes. This is especially true for searches on unique values, such as primary keys. | The Omnidex SQL Engine will evaluate the presence of native SQL Server indexes when deciding how to process a statement. At times, it may be faster to rely on the native SQL Server indexes than to use Omnidex indexes. This is especially true for searches on unique values, such as primary keys. | ||