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integration:rdbms:odbc:queries [2011/04/06 17:43] 127.0.0.1 external edit |
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| The Omnidex SQL Engine will optimize queries to take advantage of the Omnidex indexes. Many queries can be fulfilled entirely within the Omnidex indexes. This is especially true for queries that request counts or aggregations from one or more tables. Even queries that return columns of data can be completed using the Omnidex indexes, as long as all of the requested data resides in an index. | The Omnidex SQL Engine will optimize queries to take advantage of the Omnidex indexes. Many queries can be fulfilled entirely within the Omnidex indexes. This is especially true for queries that request counts or aggregations from one or more tables. Even queries that return columns of data can be completed using the Omnidex indexes, as long as all of the requested data resides in an index. | ||
| - | Other queries will require access to the underlying ODBC data. The Omnidex SQL Engine will determine how to combine the results from the Omnidex indexes with the data from the ODBC database. Usually, this requires that Omnidex provide ODBC rowids or primary keys and request rows from the ODBC tables based on those values. Other times, Omnidex may issue a more complex statement to ODBC, asking it to perform a larger role in processing the query. | + | Other queries will require access to the underlying database. The Omnidex SQL Engine will determine how to combine the results from the Omnidex indexes with the data from the underlying database. Usually, this requires that Omnidex provide primary keys and request rows from the underlying tables based on those values. Other times, Omnidex may issue a more complex statement through ODBC, asking it to perform a larger role in processing the query. |
| - | In all cases, Omnidex will access the data in the ODBC database using standard ODBC SQL statements issued using the ODBC OBDC Connector. | + | In all cases, Omnidex will access the data using standard SQL statements issued to the underlying database's ODBC driver. |
| === ODBC-specific Syntax === | === ODBC-specific Syntax === | ||
| - | Omnidex requires that all statements use Omnidex SQL syntax. Omnidex SQL uses ANSI SQL as a base, but also allows extensions from various databases, as well as Omnidex-specific extensions. Other ODBC-specific syntax will cause errors when submitted to Omnidex. In these situations, the statements must be converted to Omnidex SQL. | + | Omnidex requires that all statements use Omnidex SQL syntax. Omnidex SQL uses ANSI SQL as a base, but also allows extensions from various databases, as well as Omnidex-specific extensions. ODBC-specific syntax may cause errors when submitted to Omnidex. In these situations, the statements must be converted to Omnidex SQL. |
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