Frames MD3
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Manage Primary Key MD3

Add variable(s). Add aggregate frame(s). Remove variable or aggregate frame.

In a normal frame a primary key is mandatory. It is guarded by the integrity checker. It can consist of one or more variables, one or more aggregate frames of the frame, or a combination of both. Thus a "composite" primary key can exist, formed by all its variables together with all variables of the aggregate frame(s). They are used in the order of occurrence in frame and aggregate frame(s).

An aggregate frame never acts independently. It always belongs to (is contained by) one normal frame (or more frames). It cannot have its own primary key. But as a whole it can be (part of) the primary key of a containing frame.

lq9mar21. TO BE DISCUSSED. Aggr.frame in PK not yet implemented (it IS in MD2).

Add variable(s)
  1. Open the frame properties.
  2. In Inspector tab Specification section Primary key do one of the next:
    • Right-click and select Add Variable to Primary Key
    • Click the button with the plus-sign
  3. A list with the variables in the frame appears. Do one of the next:
    • Double-click a variable in the list. It becomes part of the primary key.
    • Select one variable. Click button Insert Variable. It becomes part of the primary key.
    • Hold down the command key. Select more variables. Click button Insert Variable. All chosen variables become part of the primary key.
Add aggregate frame(s) (still to implement)
  1. Open the frame properties.
  2. In Inspector tab Specification section Primary key do one of the next:
    • Right-click and select Add Aggregate Frame to Primary Key.
    • (Click button plus-sign? Do not know.)
  3. A list with the aggragate frames in the frame appears. Select one and double-click, or click the button Add Aggregate Frame. It is now part of the primary key.
Remove variable or aggregate frame
  1. Open the frame properties.
  2. In Inspector tab Specification section Primary key do one of the next:
    • Right-click a variable or aggregate frame and select Remove variable (aggr) from Primary Key.
    • Select a variable or aggregate frame and click the button with the minus-sign.