In this step you can choose the filter type and enter the filter criteria. You can use various types of filters in Cross Database Comparison to restrict the data being compared for the sources. You can create filters for both source systems or for one source only. (Further details about filtering see Filtering in Cross Database Comparison).

To maintain filter for the first or the second source system, choose Comparison in Edit mode. 

Choose the field in the data model for that you want to set filter. If you want to use an instance filter, set the check box. If you want to use object filter, enter the filter value. 

You can enter a filter type for a variable filter which allows that the filter values in the comparison instance can be entered in a field with the correct data type. Use the dropdown list box to select the correct filter type. Use the special filter type “relative timestamp” to enter relative timestamps in the comparison instance. (Further details about filtering see Filtering in Cross Database Comparison)

In the Instance Specific Filters screen area, specify values for the instance specific filters. You can create multiple comparison instances with different instance specific filters for the same comparison object. The data type of the fields depends on the filter type you entered during comparison object creation. If you chose filter type “relative timestamp”, you can use relative timestamps. (See Using relative date syntax) 

In the Cross Database Comparison (CDC) application, you usually extract only data, which is needed for the comparison. You can now extract further context fields just for information purpose on the comparison result UI.

There are two types of the context fields:

• The field is only available in one of the source systems (e.g. some native key field or additional attribute), and therefore cannot be included as a common mapping field
• The field is available in both source systems but always has different content (e.g. created-by fields) by purpose, and therefore is not suitable as a mapping/comparison field

On selecting the context field, an icon appears on the field of the data model.

In this step, you specify which data fields in the tables in the first system you want to compare with which data fields in the tables in the second system and which data fields are used as comparison keys. You assign this mapping a name with which you can later identify it.

You also create fixed and variables filters that you use to restrict the comparison. For fixed filters, you specify the data field and the exact value of the filter as soon as you create the comparison object. For example, you specify the restriction Country="DE" when you create the comparison object.

For variable filters, you specify when you create the comparison object that a certain data field is to be used as a variable filter, for example the Country data field. The variable filters are displayed in the comparison instance, where you can specify values for them, such as Country="DE". This allows you to create multiple comparison instances for the same comparison object and specify different filter values for each – for example, Country="DE" for one comparison instance and Country="IN" for another comparison instance.

Procedure

• Choose Comparison → Edit.
• Define the assignment by dragging the arrows provided between the tables from left to right.

  • A dialog box is displayed for each mapping assignment.

  

• Enter the following data:

  • Tag Name: Enter a name for the assignment.
  • Comparison Key No.: You create at least one comparison key for the comparison and specify the sequence of the comparison keys.

• Enter 1, 2, 3, and so on, to define the sequence of the comparison keys. Leave the field empty (0) for the data fields for the actual comparison.
  Ideally you can use the primary keys of the source tables as a comparison key. Alternatively make sure you chose another unique secondary key. It is mandatory to extract a unique and sorted comparison key. Extracting non-unique (=duplicated) comparison keys from a source system will later on result in a termination of the comparison run.

• Variable Filter: Enter X to indicate that the assignment is a variable filter.
  If you do not want to use the assignment as a filter, leave the field empty.

• You have the possibility to enter a filter type for the variable filter which allows that the filter values in the comparison instance can be entered in a field with the correct data type. Use the dropdown list box to select the correct filter type. Use the special filter type “relative timestamp” to enter relative timestamps in the comparison instance. For further details about filtering see Filtering Data

• You have the possibility to choose pre-defined conversion IDs (such as delete leading zeroes, convert to upper case) for both source systems that allow you to convert the data before it is compared. You can also define and use your own conversion IDs by creating an implementation for enhancement spot DSWP_CDC_CONVERSION and entering the conversion ID in maintenance view CDC_V_CONV_TYPE. For further details about data conversion see Conversions

• To undo the mapping, select the filed, right click and delete the mapping

The CDC application supports iteration, which means that you have the possibility to re-compare inconsistent objects. Iteration is useful if data changes frequently. It helps you to exclude temporary differences from the comparison result. Iteration can be started automatically after the first comparison is finished or manually. To start iteration automatically, enter at least one of the following parameters:

• Maximum Number of Iterations: The maximum number of iterations that will be started automatically. If one of the exit conditions is met before the maximum number of iterations is reached, iteration will stop anyhow.
• Delay: Time delay between two iterations (in seconds)
• Exit Condition (%): Iteration stops if this percentage of inconsistent objects or a value below is reached.
• Exit Condition (total): Iteration stops if this number of inconsistent objects or a value below is reached.

Change Documents in Comparison allow to track by whom and when a field value was inserted/changed/deleted.

Supported for header data attributes, multi-lingual descriptions, source-specific parameters, variable filter criteria.

Procedure

•  To display changes, choose   Comparison → Display
• Choose →