In relational databases, the information schema is an ANSI standard set of read-only views which provide information about all of the tables, views, columns, and procedures in a database. It can be used as a source of the information which some databases make available through non-standard commands, such as the SHOW command of MySQL, the DESCRIBE command of Oracle, and the \d command of PostgreSQL.
=> select count(table_name) from information_schema.tables; count ------- 99 (1 row) => select column_name, data_type, column_default, is_nullable from information_schema.columns where table_name='alpha'; column_name | data_type | column_default | is_nullable -------------+-----------+----------------+------------- foo | integer | | YES bar | character | | YES (2 rows) => select * from information_schema.information_schema_catalog_name; catalog_name -------------- johnd (1 row)
Famous quotes containing the word information:
“Many more children observe attitudes, values and ways different from or in conflict with those of their families, social networks, and institutions. Yet today’s young people are no more mature or capable of handling the increased conflicting and often stimulating information they receive than were young people of the past, who received the information and had more adult control of and advice about the information they did receive.”
—James P. Comer (20th century)