How to Read Syntax Diagrams
The instructions follow IBM standards and use the following conventions:
- Commands and keywords appear in UPPER CASE. You may enter commands and keywords in lower or mixed case. BMC Database Director for IMS converts all entries to upper case for comparison functions.
- Variables appear in lowercase italics. A variable is information you must provide; for example a database description name (DBD) or data set name.
- If punctuation marks, parentheses, arithmetic operators, and other symbols appear in the diagram you must enter them as part of the syntax.
Read syntax diagrams from left to right and from top to bottom, following the path of the line. As you follow the path of a syntax statement, you will encounter the following symbols:
Denotes the beginning of a complete syntax statement.
Denotes the end of a complete syntax statement.
Figure 1. Basic Syntax Diagram
When syntax statements are too long to fit on a single line, the following two symbols indicate a continuation. These symbols denote the beginning and end of a syntactical unit that is not a complete statement.
Indicates the statement continues on the next line.
Indicates the statement is continued from the previous line.
Figure 2. Statement Continuation
Required items appear on a main line, while optional items are placed below the main line.
Figure 3. Required and Optional Items
When you see two or more items stacked vertically, you have a choice:
- If the first item in the stack appears on the main line, you must choose at least one of the items. In some cases, you can choose only one item and in other cases you can choose more than one item in the stack. This information is noted with the individual syntax diagram.
- If the entire stack of options appear below the main line, making a choice is optional.
Figure 4. Multiple Choices
When you see an item above the main line of the syntax diagram, it indicates that the item is the default choice, with the remaining choices shown below the line as usual.
Figure 5. Default Option
When you see an arrow in the diagram, it indicates one of the following actions:
- You can choose that item more than once.
- You can select one item and then select another, but in general you cannot select the same item more than once.
Figure 6. Repeatable Items
If the repeat arrow contains a comma as follows, you must separate repeated options with a comma or a space.
Figure 7. Separating Repeated Items
