Relational Database Features

Tabular Structure of Indexed File Data

The fundamental concept behind relational databases is the organization of data within collections of tables consisting of columns and rows. Micro Focus XDBC creates a database by restructuring COBOL data files into tables. It does this by importing extended File Descriptor (XFD) files, which the compiler can generate to describe schema information to be associated with the COBOL data files in your application. XFDs enable the Micro Focus XDBC interface to populate tables in a system catalog that map COBOL records in the indexed, relative, or binary sequential file to rows and columns of data that can be accessed by common SQL commands. For more detailed information about XFDs, see the chapter Preparing your COBOL.

System Catalog

Special utilities included with Micro Focus XDBC create and populate a system catalog with information obtained from your XFDs. No special restructuring of your data files is necessary to gain the relational database-like functionality.

SQL DDL (Data Definition Language) Support

Micro Focus XDBC supports many of the DDL commands such as CREATE and DROP, enabling users to create and delete tables or views based on conditional operators and multiple fields/columns.

SQL DML (Data Manipulation Language) Enhancements

In addition to DDL support, Micro Focus XDBC includes broader and more complete support for DML commands such as UNION, UNION ALL, and combined inner/outer joins, as well as an optimized ORDER BY clause.

Multi-level Security

Through the use of the DDL commands GRANT and REVOKE, you have data security options at both database-wide and object-specific levels. For example, one table from a database can be read-only for certain users, while another table within the same database can be read/write accessible by either the same or different users. By combining views and object-level security, even column-level security is available.

Enhanced Performance

Micro Focus XDBC's optimized drivers and SQL processor result in fast execution of complex SQL commands on large data sets.