Display format for data in a relational database. The columns or database fields of the database tables in AS ABAP are defined in ABAP Dictionary. Each database table has a unique primary index and can have additional secondary indexes. Foreign key dependencies can exist between individual database tables. A database table is generally defined as a transparent table in the database of AS ABAP. Besides transparent tables there are also SAP-specific variants such as cluster tables and pooled tables. All database tables defined in ABAP Dictionary can be referenced as a data type (as with flat structures) and you can access them using Open SQL. During development, the content of database tables can be checked using Data Browser.