# Structure validation for EDI

When you switch on the Structure validation for EDI, the runtime performs additional EDI-specific syntax validations.

The syntax validation rules are configured according to the EDI specifications. These values come from the X12.org tables: ![EDI tab.](https://help.qlik.com/talend/en-US/data-mapper-specifications/Resources/images/tdm_x12.png)

The following lists the error messages that the syntax rules checker produces:

* SyntaxRules\_Conditional=Conditional (If first present, all must be present.)
* SyntaxRules\_Exclusion=Exclusion (Not more than one can be present.)
* SyntaxRules\_InvalidRuleType=Invalid rule type
* SyntaxRules\_InvalidSeqNumberList=Invalid sequence number list
* SyntaxRules\_ListConditional=List Conditional (If first present, one of the remaining items must be present.)
* SyntaxRules\_Paired=Paired (If present, all must be present.)
* SyntaxRules\_Required=Required (At least one must be present.)
* SyntaxRules\_RequiredElemNotPresent=Required element not present at
* SyntaxRules\_SeqNumberNotFound=Sequence number not found