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  • Handling a deleted record
  • Number of deleted records
  • Deleting a record from a query
  • Version of data file
  • Size of the data file
  • Deletion and lock
  • xBase/FoxFro
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Stored procedures
Deletes a record from a data file (query or view). The record is deleted logically and physically. It cannot be restored (unlike the records crossed by HCross).
The following operations are performed:
  • the record is deleted: the record is inactive and it is not referenced in the index anymore. The data is not kept.
  • the indexes (corresponding to the record keys) are deleted from the index file.
  • the memos associated with the record are deleted from the memo file.
After the call to HDelete, the record is inserted in the list of records deleted from the data file and it will be re-used by HAdd.
OLE DBNative Connectors (Native Accesses) The deleted record is no longer visible by the browse on the current item. This record will no longer be visible for the browses on the other items once these browse operations have been re-initialized.
WINDEV, WINDEV Mobile and WEBDEV offer automatic error management for the following 5 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: To delete all records of a data file, use the HDeleteAll function.
Versions 18 and later
Universal Windows 10 App This function is now available in Windows Store apps mode.
New in version 18
Universal Windows 10 App This function is now available in Windows Store apps mode.
Universal Windows 10 App This function is now available in Windows Store apps mode.
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
Versions 21 and later
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
New in version 21
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Example
WINDEVUniversal Windows 10 AppJavaHFSQLHFSQL Client/ServerHyper File 5.5
// Deletes the record #123
HDelete(Customer, 123)
// Delete the customer orders
HReadSeekFirst(ORDERS, CUSTNUM, ValCustNum)
WHILE HFound() = True
        HDelete()
        HReadNext()
END
// Delete the customer orders
FOR EACH ORDER WHERE CUSTNUM = CustNumVal
HDelete()
END
Syntax
<Result> = HDelete([<Data file> [, <Record number> [, <Options>]]])
<Result>: Boolean
  • True if the record was deleted,
  • False if a problem occurred (locked record, etc. (see the special cases)). HErrorInfo is used to identify the error.
If the record to delete is already deleted, HDelete returns True.
<Data file>: Optional character string (with or without quotes)
Name of HFSQL data file or view used. If this parameter corresponds to an empty string (""), the HDelete function manipulates the last data file used by the last HFSQL management function (function starting with the letter H).
<Record number>: Optional integer
Number of the record to delete. If this parameter is not specified (if it is equal to 0 or to the hCurrentRecNum constant), the current record will be deleted. However, the current record will remain the deleted record.

CAUTION: Do not confuse the record number with the automatic identifier associated with the record.
In most cases, these two numbers are not identical. The record number is returned by HRecNum.
OLE DBNative Connectors (Native Accesses) This parameter must correspond to the current record number (hCurrentRecNum constant).
Java Access by JDBC: This parameter must correspond to the current record number (hCurrentRecNum constant).
<Options>: Optional constant
Configures the integrity management performed on the deleted record.
hIgnoreIntegrityIgnores the integrity check for this operation, even if the automatic integrity check is enabled (HSetIntegrity)
Java Access by JDBC: This parameter is ignored.
Remarks
WINDEVUniversal Windows 10 AppJavaExternal languageHFSQLHFSQL Client/ServerHyper File 5.5

Handling a deleted record

WINDEVUniversal Windows 10 AppJavaExternal languageHFSQLHFSQL Client/ServerHyper File 5.5

Number of deleted records

HNbRec is used to find out the number of records deleted from the data file.
Remark: For backward compatibility with Hyper File 5.5, the H.NbDel variable can also be used to find out the number of deleted records.

Deleting a record from a query

Deleting a record from a query can be performed:
  • in the query result
  • in the data files handled by the query (hModifyFile constant used in HExecuteQuery or HExecuteSQLQuery). In this case, the hWithFilter constant is automatically selected.
Regardless of how the request is executed (with or without the hAh constant with SCHTRIME filter), the HDelete function can only be used on single file requests.
Caution:
  • On data files not in HFSQL format, there is no need to specify the hModifyFile constant in HExecuteQuery or HExecuteSQLQuery: the data files taking part in the query are automatically modified when modifying the query result.
  • No record can be deleted from a query that is using the groups or aggregates.
  • The management of integrity and duplicates is not performed during the operations on the multi-file queries: we recommend that you use the transactions to avoid any problem.
See Modifying the query content for more details.
WINDEVUniversal Windows 10 AppJavaExternal languageHFSQLHFSQL Client/ServerHyper File 5.5

Version of data file

If the HDelete function is successful, the version number of the data file is changed. This version number is returned by HVersion.
WINDEVUniversal Windows 10 AppJavaExternal languageHFSQLHFSQL Client/ServerHyper File 5.5

Size of the data file

The deletion of one or more records has no incidence on the total file size on disk. The locations left empty in the data files by the deletions will be re-used during the next additions of records (HAdd). This feature is used to get better performances, the reduction of file size being costly in time.
However, if after many deletions, it is necessary to reduce the size of a data file, it is possible to re-index it (via the HIndex function, the WDMap tool or the HFSQL Control Center).
WINDEVUniversal Windows 10 AppJavaExternal languageHFSQLHFSQL Client/ServerHyper File 5.5OLE DBNative Connectors (Native Accesses)

Deletion and lock

If a lock problem occurs when "deleting" a record (attempt to delete a record locked in write mode for example), the record is not deleted and HErrorLock returns True.
WINDEVNative Connectors (Native Accesses)

xBase/FoxFro

HDelete and HCross have the same effect: the record is crossed but it is not deleted. Therefore, the record can be re-enabled by HModify. In this case, function HState returns the constant h StateRaye on a deleted record (and not the constant h StateSup).
To physically delete the crossed records, you must use HIndex.
FoxPro files: HIndex is not available
Component : wd250hf.dll
Minimum version required
  • Version 9
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