What exactly is a database schema? [closed]

What exactly is a database schema? [closed]

References

Reference NO 1

http://stackoverflow.com/questions/15191555/what-exactly-is-a-database-schema

Reference NO 2

http://en.wikipedia.org/wiki/Database_schema

Reference NO 3

http://wiki.answers.com/Q/What_is_a_database_schema

Reference NO 4

http://www.postgresql.org/docs/8.1/static/ddl-schemas.html

Reference NO 5

https://drupal.org/node/1734950

Reference NO 6

http://docs.sqlalchemy.org/en/rel_0_7/core/schema.html

Reference NO 7

http://dba.stackexchange.com/questions/21304/multi-tenant-database-schema-creation

Reference NO 8

http://www.oracle.com/technetwork/articles/sql/11g-schemamanagement-089869.html