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  • Deleting records from a query
  • Deleting records from a HFSQL view
  • Deleting records from a transaction
  • Benefits compared to a loop for deleting records
  • Benefit compared to the use of HCreation
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Stored procedures
HDeleteAll (Function)
In french: HSupprimeTout
ODBCNot available with this kind of connection
Deletes all records from a data file, a HFSQL view or a query. The records are deleted logically and physically. They cannot be restored.
The following operations are performed:
  • the records are deleted: the records are not referenced in the index anymore. The data is not kept.
  • the indexes (corresponding to the keys of the records) are deleted from the index file.
  • the memos associated with the records are deleted from the memo file.
  • the automatic identifiers are re-initialized.
Caution: the integrity is not checked.
WINDEV, WINDEV Mobile and WEBDEV propose an automatic management of errors for the following types of errors: Duplicate error, integrity error, password error, modification conflict error and status error during modification conflict, lock error. See Assisted management of HFSQL errors for more details.
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
Example
// Clears the file without re-creating it
HDeleteAll(Customer)
Syntax
<Result> = HDeleteAll(<File name>)
<Result>: Boolean
  • True if the records have been deleted,
  • False if a problem occurred (locked record, record in transaction, ...). HErrorInfo is used to identify the error.
<File name>: Character string (with or without quotes)
Name of HFSQL data file, HFSQL view or query used.
Remarks

Deleting records from a query

If the query was created by using the hModifyFile constant, HDeleteAll deletes the records from the source of the query.

Deleting records from a HFSQL view

HDeleteAll deletes the records from the view but it does not delete the records from the data file used for the view.

Deleting records from a transaction

HDeleteAll does not delete the records found in a transaction (canceled or validated).

Benefits compared to a loop for deleting records

To delete the records from a data file, you also have the ability to perform a loop for deleting records (HDelete). For example:
FOR EACH CustNum OF Orders
        HDelete()
END
Using HDeleteAll presents the following benefits:
  • the process is faster
  • the size of empty data file is smaller.

Benefit compared to the use of HCreation

To delete the records from a data file, you also have the ability to use HCreation.
Using HDeleteAll presents the following benefits:
  • Deletion possible even if users are connected to the data file.
  • Automatic management of HFSQL errors.
Component : wd250hf.dll
Minimum version required
  • Version 14
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