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Delete commandOfficial Content

Deletes the record in the base table associated with the group where the Delete command is specified.

Syntax

Delete

Description

This command is used to delete records in the Base Table associated with the group where the Delete command itself is specified.

A Delete command can only be used in a For Each command (X Evolution 2). The deletion is executed at the exact moment the Delete command is encountered, unless the For each command has a Blocking clause. In this last case, the actual deletion will happen when the entire block is completed and a Delete command is sent to the DBMS for a bulk deletion.

Notes

  • Referential Integrity - this is NOT automatically checked when the Delete command is specified.
  • If the Delete command is specified in a group that has nested groups, data in the current group can be used in the inner nested groups, even though it has been physically deleted.
  • Remember to delete the inner levels first, before the outer levels. This avoids any possible cancellations or locks.

Example

Given the tables:

PurchaseOrder
PurchaseOrderId*
PurchaseOrderDate
SupplierId
PurchaseOrderAmount

PurchaseOrderDetail
PurchaseOrderId*
PurchaseOrderDetailId*
PurchaseOrderDetailQuantity
PurchaseOrderDetailPrice
PurchaseOrderDetailAmount

Here, purchase order lines are deleted before the purchase order header, so if the program were to cancel, there would be no purchase order lines left without a header.

For each   //Header
   where PurchaseOrderDate <= &LimitDate
   For each
   Defined by PurchaseOrderDetailPrice
      Delete
   Endfor
   Delete
EndFor
To learn how to improve the throughput of bulk deletions, see Blocking clause in a 'For each' command or the general concept on Blocking Data Updates.

Scope

Objects    Procedure object




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