Unique Constraints

Often, it is necessary to prevent users from creating instances with duplicate values. There might be some fieldsFieldA property of a DataElement expanded to a database column and user interface input element. that are used as keys to uniquely identify an instance. Or perhaps you might want to prevent wild growth of data.

To enforce this, each DataElement can have one or more UniqueConstraints.

Each one lists a number of FieldsFieldA property of a DataElement expanded to a database column and user interface input element.. The constraint will generate a check to make sure it is not possible to create 2 instances with the same values for these FieldsFieldA property of a DataElement expanded to a database column and user interface input element..

Document.xml

<dataElement name="Document">
  <fields>
    <field name="name">
      <!-- ... -->
    </field>
  </fields>
  <uniqueConstraints>
    <uniqueConstraint>
      <fields>
        <field component="documents" dataElement="Document" name="name"/>
      </fields>
    </uniqueConstraint>
  </uniqueConstraints>
</dataElement>

UniqueKey option

UniqueConstraints replace the option uniqueKey and improve on it:

• You can have more than one UniqueConstraints
• The check uses a dedicated query instead of a FinderFinderA search specification combining field-operator pairs to execute standard data queries on a DataElement., so that it will work even for null values.
• No need to explicitly define a FinderFinderA search specification combining field-operator pairs to execute standard data queries on a DataElement.
• No more loosely typed String to define the FieldsFieldA property of a DataElement expanded to a database column and user interface input element.

Option

uniqueKey DeprecatedDataElement

Deprecated

Use UniqueConstraints instead.

Adds a validation that checks for any duplicates based on the provided set of FieldsFieldA property of a DataElement expanded to a database column and user interface input element..

The fieldFieldA property of a DataElement expanded to a database column and user interface input element. name or list of fieldFieldA property of a DataElement expanded to a database column and user interface input element. names provided as the option value determine the unique key of the DataElement. When specifying a list of fieldFieldA property of a DataElement expanded to a database column and user interface input element. names, these should be separated by underscores.

It will reject any new instances that has the same values for these FieldsFieldA property of a DataElement expanded to a database column and user interface input element. as an instance that already exists in the database. Likewise, it will also prevent any updates that would create a collision with another instance.

The uniqueness is enforced at the logic level. A {DataElement}UniquenessValidation class is generated which exposes a checkUnique method. Internally, a finderFinderA search specification combining field-operator pairs to execute standard data queries on a DataElement. using the combination of the provided fieldsFieldA property of a DataElement expanded to a database column and user interface input element. is then used to retrieve already existing instances. If a finderFinderA search specification combining field-operator pairs to execute standard data queries on a DataElement. artifactArtifactA build or deployment result, such as a Docker container image or Java archive, produced by a software project. for the combination of fieldsFieldA property of a DataElement expanded to a database column and user interface input element. does not exist in the model, it will be automatically generated and added to the model. The checkUnique() method is invoked by the create and modify methods of the {DataElement}Bean.

<options>
  <uniqueKey>name_version</uniqueKey>
</options>