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.