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SQL Development
Performing Multi-database Queries : Multi-database query overview : Working with catalogs in multi-database queries
 

Working with catalogs in multi-database queries

All data references in SQL follow a syntax where a reference has from one to four components of the form catalog.schema.table.column.
OpenEdge SQL uses database naming conventions shown in the following table, which are in full compliance with the SQL standard.
Table 13. OpenEdge SQL Database Naming Conventions
Terms
Definition
Catalog
A named collection of schemas. In OpenEdge SQL, a catalog logically corresponds to a database.
Schema
A collection of tables and other database objects.
Table
A collection of data organized into columns and rows.
Catalogs are used as name components to identify columns and tables in a multi-database query. A table name can have up to three components: catalog.schema.table-name. A column name can have up to four components: catalog.schema.table.column-name.
The primary database—already connected when an OpenEdge SQL process attaches to the OpenEdge SQL Server—is already assigned the name of the primary database as its catalog name. Each auxiliary database is assigned a name when the CONNECT AS CATALOG command is executed.
Note: Catalogs cannot be used in Data Definition Language statements such as ALTER and CREATE. Nor can they be used with sequences.
* Working with default catalogs
* Working with catalogs and synonyms
* Working with catalogs and stored procedures
* Granting permissions to perform multi-database queries
* Limitations of the OpenEdge SQL multi-database environment