Difference Between LinkType and JoinType in Dynamics Ax 2012

Hi Everyone today i would like share information on Link types and Join Types. 

• Link type is a property of the form data source. We can add more than one tables as a data source to the form.
• Those data sources should have the table level relation, So, that the developer don't need to work on the coding part to find the related records. 

For example, if we create the order form, that order form has orders and orderdetails tables as form data sources. We can add both tables as a data sources to the form.

Link Type:

•  Active:  Parent and child- data source is updated immediately when a new record in the parent data source is selected. Continuous updates consume lots of resources consuming.

•  Delayed: Parent and child - A pause is inserted before linked child data sources are updated. This enables faster navigation in the parent data source because the records from child data sources are not updated immediately. For example, you can scroll a list of orders where you do not want to review the lines associated with the order until you stop scrolling.

•  Passive: Parent and child - Linked child data sources are not updated automatically. Updates of the child datasource must be programmed on the active method and executequery of the master data source.

Join Types:

• InnerJoin:  Combined data source – select the record from the main table that matches records in the joined table and vice versa. There is one record for each match. Records without related records in the other data source are eliminated from the result.
• Outer Join:  Combined data source – select the records from the main table. The records are retrieved whether they have matching records in the joined table.
• Exist Join:  Combined data source -The data source retrieves a record from the main table for each matching record in the joined table.
• NotExistJoin:  Combined data source -Select records from the main table that do not have a match in the joined table.

Differences Between InnerJoin and ExistJoin are as follows:

• When the join type is ExistJoin, the search ends after the 1st match has been found in the child datasource.
• When the join type is InnerJoin, all matching records are searched for.

Proud To Be a DAX Developer :-)