Walkthrough: Creating a Valid Time State Table

Articolo
05/18/2015

Applies To: Microsoft Dynamics AX 2012 R3, Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012

The scenario in this topic illustrates how to create a valid time state table in Microsoft Dynamics AX.

Date effective data is tracked in a table that has its ValidTimeStateFieldType changed from its default value of None. Also, an index with its ValidTimeStateKey set to Yes must be added on the table. The system automatically adds the fields named ValidFrom and ValidTo to the table, which will be of type date or utcdatetime. The system automatically prevents overlap between the date ranges in these two fields among rows that track the same entity.

Prerequisites

Before you read this topic, you should know how create a table, add fields to it, and add an index. For more information, see the following topics:

Introduction to Scenario

In this scenario the many-to-many relationship between employees and the projects they work on is tracked by date ranges. For example, for any date, a query can obtain a list of all the employees associated with a given project. In the test table, the fields EmplID and ProjID are considered to be foreign key fields.

In this scenario we choose to permit gaps between the date ranges in rows that differ only in their ValidFrom and ValidTo values.

In this scenario you:

Create a table and add fields.
Prompt the system to automatically add ValidFrom and ValidTo date fields.
Create an alternate key index that includes the ValidFrom and ValidTo fields, plus at least one more field.
Set properties on the index.

Create a Table and Add Fields to the Valid State Table

Create a table as follows:

In the AOT, create a table. Name the table TabEmplProjVts.
Add the following string fields to the table:
- EmplID
- ProjID
- EPPrimaryKey

Add ValidFrom and ValidTo Date Fields

The system automatically adds the fields ValidFrom and ValidTo to the table when you change the ValidTimeStateFieldType from its default of None. These system fields cannot be disabled by configuration keys.

To add the ValidFrom and ValidTo date fields to the table, you set a property on the table. Do as follows:

In the Properties window for the table TabEmplProjVts, set the ValidTimeStateFieldType property to Date.

Note

You can change the ValidTimeStateFieldType to any value when the table contains no data. You can change the value to None even if the table contains data.
At the node AOT > Data Dictionary > Tables > TabEmplProjVts > Fields > ValidFrom, right-click and select Properties.
Verify that the Mandatory property is set to Yes.

Create an Alternate Key Index that Includes ValidFrom

In this section you put both of the foreign key fields EmplID and ProjID into an alternate key index. Then you add the ValidFrom and ValidTo fields, and set properties on the index. Do as follows:

At the node AOT > Data Dictionary > Tables > TabEmplProjVts > Indexes, right-click and select New Index.
In the Properties window for the new index, set the Name property to idxEPAltKeyVts.
Right-click the idxEPAltKeyVts node, and then select New Field.
In the Properties window for the newly added field, override the default field name and select EmplID.
Add the ProjID field to the index.
Add the ValidFrom field to the index.
Add the ValidTo field to the index.

Set Properties on the Index

To configure the index to support date effective data, you must set the properties on the index idxEPAltKeyVts as follows:

Set AllowDuplicates to No.
Set Alternate Key to Yes.
Set ValidTimeStateKey to Yes.
Set ValidTimeStateMode to Gap.

Note

You can change the ValidTimeStateMode property from Gap to NoGap only if the table contains no data. You can change from NoGap to Gap even if the table contains data.

Final Steps

If you want to continue with the data phase of this scenario, see Effects of Valid Time State Tables on Read and Write Operations.

For information about controlling the cardinality of relationships in a valid time state table, see Cardinality in Valid Time State Table Relationships.

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