Initially released in 1971 on IBM mainframe systems using DOS/360, OS/MFT or OS/MVT, ADABAS, as of 2014, is available on a range of other systems including Unix, Linux, and Microsoft Windows servers. ADABAS has Parallel Sysplex support, real-time replication capability, and SQL and XML access. Historically, ADABAS was used in conjunction with Software AG's programming language NATURAL, so that many legacy applications that use ADABAS as a database on the back-end are developed with NATURAL.
ADABAS is an inverted list database, with the following characteristics:
Files, not tables, as the major organizational unit
Records, not rows, as content unit within the organizational unit
Fields, not columns, as components of a content unit
No embedded SQL engine. SQL or another external query mechanism must be provided. SQL access is provided by the ADABAS SQL gateway. It provides ODBC, JDBC and OLE DB access to Adabas and enables SQL access to ADABAS using COBOL programs.
Search facilities may use indexed fields or non indexed fields or both.
Does not natively enforce referential integrity constraints, i.e. parent-child relations must be maintained by application code.
Supports two methods of denormalization: repeating groups in a record ("periodic groups"); and multiple value fields in a record ("multi-value fields").