Mainframe Blog

How to Read IBM® Syntax Diagrams for Db2 12

2 minute read
Stephen Watts

Read the syntax diagrams from left to right, from top to bottom, following the path of the line.

(This article is part of our Db2 Guide. Use the right-hand menu to navigate.)

The >>--- symbol indicates the beginning of the statement
The ---> symbol indicates that the statement syntax is continued on the next line
The >--- symbol indicates that a statement is continued from the previous line
The --->< symbol indicates the end of a statement
Diagrams of syntactical units other than complete statements start with the 
>--- symbol and end with the ---> symbol.

Required items appear on the horizontal line (the main path).


Optional items appear below the main path.


If an optional item appears above the main path, that item has no effect on the execution of the statement and is used only for readability.


If you can choose from two or more items, they appear vertically, in a stack. If you must choose one of the items, on item of the stack appears on the main path.


If choosing one of the items is optional, the entire stack appears below the main path.


If one of the items is the default, it appears above the main path and the remaining choices are shown below.


An arrow returning to the left, above the main line, indicates an item that can be repeated.


If the repeat arrow contains a comma, you must separate repeated items with a comma.


A repeat arrow above a stack indicates that you can repeat the items in the stack.

Keywords appear in uppercase (for example, FROM). They must be spelled exactly as shown. Variables appear in all lowercase letters (for example, column-name). They represent user-supplied names or values. If punctuation marks, parentheses, arithmetic operators, or other such symbols are shown, you must enter them as part of the syntax.

Disclaimer: This Db2® 12 for z/OS Reference Guide was developed to help users in their daily activities in administrating and programming in Db2 for z/OS. There are no guarantees expressed or implied with the contents in this guide. We want to provide a quality and useful reference for users. Please notify us of any mistakes or errors in this reference guide at Db2 is a registered trademark of the IBM Corporation.

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About the author

Stephen Watts

Stephen Watts (Birmingham, AL) contributes to a variety of publications including, Search Engine Journal, ITSM.Tools, IT Chronicles, DZone, and CompTIA.