====== Joints ======
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===== Standard joints =====

The tool ''Add Standard'' allows you to create automatically the links between tables:

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When joints have been modified or added manually, it is possible to add them to the Vigilens standard joints library: just use the button ''Record standard joints'', a screen allows you to select the joints then give a name to the joint.

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===== Manual Joints =====

If the necessary joints are not known to Vigilens, these links must be specified manually.

===== Add =====

The first field of the join, the relationship type, and then the second field is selected.

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===== Joint Type =====

You can choose to have an open or closed joint.

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===== Joint Conditions =====

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===== Use Case =====

<WRAP round important>
Although very similar, this section should not be confused with the "Extract according to the following rule" screen.
The filters indicated here will be applied __ before the join is made. This distinction is important in the case of open joints, as the result would not be the same.
</WRAP>


From an SQL point of view, it is the difference between

  SELECT Parent,* Child,* FROM Parent
  LEFT JOIN Child
  ON Child.Id = Parent.Id
  AND Child.Name = 'Barnabé'.

and

  SELECT Parent,* Child,* FROM Parent
  LEFT JOIN Child
  ON Child.Id = Parent.Id
  WHERE Child.Name = 'Barnabé' = 'Barnabé'.

The first case is equivalent to putting the condition on the joint: all the parents, and their children if their name is Barnabé, will be included in the selection.

The second case is equivalent to putting the condition on the "Extraction according to the following rule" screen. We will only retrieve the parents who have a child named Barnabé. The filter "killed" the open joint. 

===== Editing Criteria =====

[[:en:v8_0_0:designer:menus:accueil:nouvellerequete:criteres|See dedicated page]]

===== General conditions =====

A condition can be transferred to the general conditions list. 

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