How Can I Identify Objects Uniquely Across Different Database Vendors?

Identifying Objects in Cross-Vendor Databases

When comparing databases across vendors such as Oracle, SQL Server, DB2, MySQL, and PostgreSQL, the question arises of how to uniquely identify objects and whether a catalog is required.

Definition of Catalog

The concept of a catalog varies across database systems. In Oracle, Postgres, and DB2, a catalog is equivalent to the entire database managed by the execution engine. In SQL Server, it is synonymous with the database namespace qualifier. In MySQL, it represents a schema or namespace within the server.

Schema vs. User

A schema is a namespace within a database that groups related objects and provides access control. In Oracle and Postgres, the schema is identical to the user account who owns it. In MySQL, it is not tied to any specific user. In SQL Server, the owner is referred to as the schema.

Identifying Objects

To identify any object uniquely in a running server instance, the required parameters depend on the database implementation:

• Oracle: Schema name object name
• Postgres: Database name schema name object name
• MySQL: Database name object name
• SQL Server: Database name owner object name

Catalog Abstraction

A catalog is indeed an abstraction of data storage. It represents a self-contained isolated namespace, but not all SQL engines adhere to this definition.

Other Considerations

• Database and schema are well-defined by all vendors.
• Catalog may have different meanings depending on the context.
• Schema is recommended for organizing artifacts in SQL databases due to its access control capabilities.

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