SQL

SQL, or Structured Query Language, is a platform independent way of accessing databases. However, the version of SQL which runs on the AS/400, known as SQL400 or SQLDB2, does have syntax differences from standard SQL.

Terminology

SQL Term	iSeries Term
TABLE	PHYSICAL FILE
ROW	RECORD
COLUMN	FIELD
INDEX	KEYED LOGICAL FILE ACCESS PATH
VIEW	NON-KEYED LOGICAL FILE
SCHEMA	LIBRARY COLLECTION
LOG	JOURNAL
ISOLATION LEVEL	COMMITMENT CONTROL LEVEL

Tips

SQL7008 error

&FILE in &LIBRARY not valid for operation.

-- Code 3 -- &FILE is not journaled, or you do not have authority to the journal. Files with an RI constraint action of CASCADE, SET NULL, or SET DEFAULT must be journaled to the same journal.

• Resolution: Use RUNSQLSTM with parameter COMMIT(*NONE)

SELECT *

For the sake of example, use two files, master and trans. We want to select all the columns in trans but only the name column from table master.

If using *SYS naming you can execute SELECT trans.*, name FROM trans JOIN master ON...

If using *SQL naming, we need to use a correlation name: SELECT t.*, name FROM trans t JOIN master ON...

RUNSQL command for ad-hoc SQL statements

"Partner TechTip: Blend SQL and RPGLE to Make Better Tools" by Kevin Forsythe

See also

See also: SQL Primer and SOUNDEX

See also on Wikipedia: SQL