Sample Exam Questions

From the objective of OSS-DB Exam Silver
S2.5 Basic server administration (Information schema and system catalogs)

Sample Question


Choose three appropriate descriptions for information schemas and system catalogs.

  1. The format of the information schema is as specified in the SQL standard.

  2. The amount of information that can be seen in the information schema and the system catalog is equivalent.

  3. The PostgreSQL system catalog is defined by a schema named pg_system.

  4. The PostgreSQL system catalogs typically start with the prefix 'pg_'.

  5. The pg_database catalog does not exist for each database, but rather one for each database cluster.

※This sample exam is different from those that appear in the actual OSS-DB Exam.

Answer and Explanation

The various types of information in a database cluster are stored in the information schema, which is specified in the SQL standard, and in the system catalogs, which are specific to the database management software.
An information schema, named information_schema, contains information about tables, columns, users, and other aspects of the database. Because the information schema does not contain information specific to the database management software, the system catalog should be checked for more detailed information.
PostgreSQL's system catalogs are defined in a schema named pg_catalog and are typically prefixed with 'pg_'. There is one pg_database catalog for each database cluster, rather than one for each database.

Therefore, the correct answers are A, D, and E.