1. Basic Expression for Tracker Attributes and normal TADB Groups

Purpose

Test a selected section of an attribute's value.

Assumptions

There is one Attribute Group (in the expression), defined as follows.

Order Card

Attributes include A

Query Expression

Order Card.A,3,2='xy'

Where

Criteria	Is/are the:
A	Order card attribute
3	Position 3 in the A attribute value.
2	Return 2 characters in the A attribute value. Note: This is a character comparison dependant on the collation order of your database.
'xy'	Required characters in the A attribute value positions 3 and 4.

Query Expression says:

Determine if an Order Card A attribute value, positions 3 and 4 contains the characters xy.

bnf syntax Expression

Note: This syntax in this expression is the basis of all expressions and can be summarized in this .bnf expression.

simpleExpression ::= [notOperator] group.attribute[,position[,length]] comparisonOperator value

Where

notOperator	(!) When used, defines the remainder of the expression as what the value should not be.
Group	Either a TADB attribute group name or Reserved name Trk (refers to the collection of all standard and extended Tracker attributes).
position	Starting position in a value to begin the comparison.
length	Number of characters to compare.
	If: position is specified and length is not Then length is assumed to be 1. Neither position nor length are specified Then The entire attribute is included in the comparison.
ComparisonOperator	= < > < = >= =l =r Note: There is no Not ComparisonOperator. When an expression should be a not expression, a ! is placed before the expression. Example !Order Card.A,3,2='xy'

Tip: You can use the keyword NULL to query NULL fields in the database.

Example

When you execute a list query on:

Order Card.Target Gate Release Date=l'%'

The query returns all the items that have a release date.

Order Card.Target Gate Release Date=NULL

The query returns all the items that have a <NULL> release date.

Order Execution Mgt. Query expression descriptions.