DB2 Universal Database™ for iSeries™ provides two access methods for manipulating database tables and data: Structured Query Language (SQL) and system file access methods. They use different words to describe some similar concepts.
As an interface to DB2 Universal Database for iSeries, the DB2® UDB Query Manager and SQL Development Kit adds an interactive query and report writing interface, as well as precompilers and tools to assist in writing SQL application programs in high-level programming languages. Conforming to the industry standard Structured Query Language (SQL), the SQL implementation for i5/OS™ allows you to define, manipulate, query, and control access to your iSeries data. It works equally well with i5/OS files and SQL tables.
SQL versus traditional file access terminology
| SQL term | Traditional file access term |
|---|---|
 Collection. A group of related objects that
consists of a library, a journal, a journal receiver, an SQL catalog, and
an optional data dictionary. A collection enables the user to find the objects
by name. |
Library. A group of related objects that enables the user to find the objects by name. |
| Table. A set of columns and rows. | Physical file. A set of records. |
| Row. The horizontal part of a table containing a serial set of columns. | Record. A set of fields. |
| Column. The vertical part of a table of on data type. | Field. One of more bytes of related information of one data type. |
| View. A subset of columns and rows of one or more tables. | Logical file. A subset of fields or records of up to 32 physical files. |
| Index. A collection of data in the columns of a table, logically arranged in ascending or descending order. | Index. A type of logical file. |
| Package. An object that contains control structures for SQL statements to be used by an application server. | SQL package. An object that contains control structures for SQL statements to be used by an application server. |
| Catalog. A set of tables and views that contain information about tables, packages, views, indexes, and constraints. | No similar object. However, the Display File Description (DSPFD) and Display File Field Description (DSPFFD) commands provide some of the same information that querying an SQL catalog provides. |