A schema-Name represents a schema. Schemas contain other dictionary objects, such as tables and indexes. Schemas provide a way to name a subset of tables and other dictionary objects within a database.
You can explicitly create or drop a schema. The default user schema is the APP schema (if no user name is specified at connection time). You are not allowed to create dictionary objects in the SYS schema.
Thus, you can qualify references to tables with the schema name. When a schema-Name is not specified, the default schema name is implicitly inserted. System tables are placed in the SYS schema. You must qualify all references to system tables with the SYS schema identifier. For more information about system tables, see "Derby System Tables".
A schema is hierarchically the highest level of dictionary object, so you cannot qualify a schema-Name.
-- SAMP.EMPLOYEE is a table-Name qualified by a schema-Name SELECT COUNT(*) FROM SAMP.EMPLOYEE -- You must qualify system catalog names with their schema, SYS SELECT COUNT(*) FROM SYS.SysColumns
Table of Contents