Understanding external validation rules

External validation rules are a set of requirements used to validate the content of data being submitted in InfoSphere® MDM Custom Domain Hub transactions.

An external validation rule consists of following several validation parts: the target, context, condition, function, parameters, and definition.

• Validation target—Specifies the target data where the validation rule will be applied. There are three categories of validation based on different validation target:
  • Context only validation—There is no need to specify validation target. This type of validation has a specific validation context associated with a pre-known target data.
  • Fixed type data validation—The type metadata is stored in V_GROUP and V_ELEMENT tables for class and attribute information.

    Groups are defined in the V_GROUP table which associates a group name with an object within a specific application.

    Figure 1. V_GROUP table

    

    The V_ELEMENT table defines all the fields or attributes that make up an object (group), and associates them with element names.

    Figure 2. V_ELEMENT table

    
  • Variable type data validation—The type metadata is stored in SPECFMT table containing XSD schema information for external and internal XSD files.
    Figure 3. SPECFMT table

    
• Validation context—Specifies the context under which the validation will be executed. The context has two parts: application and transaction type. The V_TRANSACTION table is used to store the context definition.
  

  The application and transaction types group a set of related validation rules. For example, a delete operation can require different values in a field than an update operation. Most data validation rules apply across all transactions, and are assigned to a general transaction type.

  IBM® InfoSphere Master Data Management Custom Domain Hub offers four generic predefined transaction types: create, delete, general, and update. Any validation defined with transaction type of GENERAL will also apply to a transaction type of CREATE or DELETE or UPDATE. Fixed type validation and variable type validation only supports the four predefined transaction types.

  Context only data validation requires you to specify a detailed transaction name as transaction type. In this case, validation defined for this transaction type only applies to this specific transaction. For example, if you define a context only validation, you can define the context as an application of TCRM and a transaction type of addParty for a specific transaction.

• Validation condition—Decides if the validation should be executed. The validation condition points to an external rule to be evaluated. The EXTRULE table is used to store any external rules. For details about external rules, refer to Configuring external business rules The validation condition is optional.
• Validation function—Requires the V_FUNCTION table to store function information. It is pointing to a Java™ class created by the user or packaged with the InfoSphere MDM Custom Domain Hub. This Java class has to extend abstract class ValidatorCommon for the validation engine to process it. It must implement the abstract method validateObject for validation logic and override the setValidatorParameter method for any parameter initialization.
  Figure 4. V_FUNCTION table

  
• Validation parameters—Makes the function more flexible so that it can be reused. For example, a range check function can use two parameters to specify its upper bound and lower bound value. Validation parameters are associated with a specific validation rule definition and have many to one relationship. It is part of the validation definition.

  You can use a ParameterType and ParameterValue to describe a parameter. You can have multiple parameters. You can have many parameters with same ParameterType and different ParameterValue.

• Validation definition—Defines what should be validated. A full external validation definition links validation target, validation context, validation condition, validation function, and validation parameters together. It also contains an error code to be used in case validation fails. For details about error handling, refer to Configuring logging and error handling.
  There are three categories of validation definitions, one for each of the validation types:

  • Definitions for fixed type data validation—Element or attribute validation definition is stored in V_ELEMENT_VAL and V_ELEMENT_PARAM tables.
    Figure 5. V_ELEMENT_VAL table

    
    Figure 6. V_ELEMENT_PARAM table

    
    Group or cross attribute validation definition is stored in the V_GROUP_VAL and V_GROUP_PARAM tables.

    Figure 7. V_GROUP_VAL table

    

    Figure 8. V_GROUP_PARAM table

    
  • Definitions for variable type data validation—Variable data validation definition is stored in V_VAL and V_PARAM tables.
    Figure 9. V_VAL table

    
    Figure 10. V_PARAM table

    
  • Definitions for context only validation—Validation definition is stored in V_VAL and V_PARAM tables. It has no target data. The TARGET_ID column will be null.
    Figure 11. V_VAL table