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integration:rdbms:queries [2011/03/14 21:06]
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integration:rdbms:queries [2016/06/28 22:38] (current)
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 **[[integration:​rdbms:​queries|Queries]]** | **[[integration:​rdbms:​queries|Queries]]** |
 [[integration:​rdbms:​updates|Updates]] | [[integration:​rdbms:​updates|Updates]] |
-[[integration:​rdbms:​creation|Generating Data Files]] | +[[integration:​rdbms:​integration|Integration ​Guides]]
-[[integration:​rdbms:​implementation|Implementation ​Guides]]+
  
 ---- ----
 ==== Querying Relational Databases ==== ==== Querying Relational Databases ====
  
-Omnidex allows the relational database tables and the Omnidex indexes to be queried using standard SQL statements using an ODBC or JDBC interface. ​ The query optimizer within Omnidex will evaluate the SQL statement and choose the best approach for processing.  ​Many queries will be processed ​using the Omnidex indexes with no need to access the underlying relational database. ​ +=== Query Optimization === 
 + 
 +Omnidex allows the relational database tables and the Omnidex indexes to be queried using standard SQL statements using an ODBC or JDBC interface. ​ The query optimizer within Omnidex will evaluate the SQL statement and choose the best approach for processing.  ​Queries will only access the indexes or the database tables if needed. 
 + 
 +Some queries will be processed ​entirely within ​the Omnidex indexes with no need to access the underlying relational database, as shown below.
  
 {{:​integration:​rdbms:​relational_database_queries_indexes_only.png|}} {{:​integration:​rdbms:​relational_database_queries_indexes_only.png|}}
  
-Some queries may be processed ​exclusively ​in the relational database ​if Omnidex indexes ​would not improve performance.+Some queries may be processed ​entirely ​in the relational database ​with no need to access the Omnidex indexes, as shown below.
  
 {{:​integration:​rdbms:​relational_database_queries_database_only.png|}} {{:​integration:​rdbms:​relational_database_queries_database_only.png|}}
  
-Many queries will be processed using a combination of Omnidex indexes and access to the underlying relational database.  ​+Some queries will be processed using a combination of Omnidex indexes and the underlying relational database, as shown below.  ​
  
 {{:​integration:​rdbms:​relational_database_queries_combined.png|}} {{:​integration:​rdbms:​relational_database_queries_combined.png|}}
  
-Queries can be submitted using Omnidex SQL.  Omnidex SQL consists of ANSI SQL, supplemented with [[dev:​sql:​functions:​home|Omnidex functions]].  Omnidex also supports ​some of the proprietary functions found in the relational ​database.  Access to these relational database extensions can be controlled using the [[dev:​sql:​statements:​set_sql_syntax|SET SQL_SYNTAX]] statement. ​ Applications ​that have been using a particular SQL dialect from a relational database will need to adjust their syntax to Omnidex SQL.+=== Omnidex SQL === 
 + 
 +Queries can be submitted using the Omnidex SQL language.  Omnidex SQL consists of ANSI SQL, supplemented with Omnidex ​extensions and functions. ​ Omnidex also supports ​a limited number ​of proprietary functions found in the popular ​relational ​databases.  Access to these relational database extensions can be controlled using the [[dev:​sql:​statements:​set_sql_syntax|SET SQL_SYNTAX]] statement. ​ Applications using a particular SQL dialect from a relational database will need to have the syntax ​adjusted ​to Omnidex SQL.
  
-Some queries can benefit from rewording or restructuring,​ though ​Omnidex will attempt to optimize ​query as it is originally worded.  ​Nonetheless, many poor-performing relational queries have been customized by talented and hard-working database administrators to achieve the best performance for the underlying relational database. ​ This may not lead to the best performance with Omnidex. ​ Consult the documentation on [[admin:​optimization:​home|optimizing queries]] to understand more about how queries can be optimally structured for Omnidex.+Omnidex will attempt to optimize ​all queries; however, like the relational databases, queries can sometimes be tuned by restructuring or reorganizing the query.  ​Omnidex does favor certain approaches to queries. ​ Additionally, many poor-performing relational queries have been customized by talented and hard-working database administrators to achieve the best performance for the underlying relational database. ​ This may not lead to the best performance with Omnidex. ​ Consult the documentation on [[admin:​optimization:​home|optimizing queries]] to understand more about how queries can be optimally structured for Omnidex.
  
  
 
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integration/rdbms/queries.1300136814.txt.gz · Last modified: 2016/06/28 22:38 (external edit)