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  • Read operation according to a key item or not
  • Locks
  • Memos
  • Password
  • Various
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Stored procedures
Positions on the last file record according to a search item. The record is read and the HFSQL variables are updated (e. g. Customer.Name, in other words, the Name item in the Customer data file).
The reading is performed for the greatest value of search item (see remarks for more details).
In most cases, HReadLast is used to position in the data file in order to perform a read loop with HReadPrevious.
Several cases may occur after the call to HReadLast:
  • the data file is empty or no record corresponds to the filter (defined by HFilter): no reading is performed and HOut returns True.
  • the function tries to lock a record that is already locked in read-only: no reading is performed, HErrorLock returns True and HOut returns True.

    PHP The management of locks is not available.
This function can be used with the data files, HFSQL views or queries. Note: From version 19, HFSQL is the new name of HyperFileSQL.
HReadLast(Customer, Name)
WHILE HOut() = False
        // Process the record
        HReadPrevious(Customer, Name)
END
Syntax
<Result> = HReadLast([<Data file> [, <Browse item>] [, <Options>]])
<Result>: Boolean
Corresponds to:
  • False if an error occurred. In this case, HError returns an integer other than 0. HErrorInfo returns more details about the error. The record is not read.
  • the value of HFound in the other cases (the record can be read, even if <Result> returns False).
<Data file>: Optional character string (with or without quotes)
Name of data file, HFSQL view or query used.
If this parameter corresponds to an empty string (""), HReadLast uses the last data file used by the last HFSQL management function (function starting with "H").
<Browse item>: Optional character string (with or without quotes)
Name of item used to browse the data file or the view. If this name is not specified, HReadLast will use:
  • For a data file: the last browse item used on this file by the last function for HFSQL management (starting with the letter H). If this item does not exist, the best browse item is automatically used.
  • For a query: the ORDER BY of the query (if it exists), otherwise the last item used.
  • For a view: the sort item of view (if it exists), otherwise the last item used.
<Options>: Optional constant (or combination of constants)
Configures:
  • the lock performed on the record read by HReadLast.
  • whether the filter that was defined must be taken into account.
hLockNoNo lock (even if HStartLock was called): the record can be read or modified by another application during the reading.

PHP This constant is not available.

hLockWriteLock in write mode: the record currently read can be read by another application but it cannot be modified by another application.

PHP This constant is not available.

hLockReadWriteLock in read/write: the record currently read cannot be read or modified by another application.

OLE DB Lock in write-only. Operating mode equivalent to the hLockWrite constant.

PHP This constant is not available.

Versions 17 and later
hForwardOnly
New in version 17
hForwardOnly
hForwardOnly
Native Connectors (Native Accesses) Constant that can only be used with Native Connectors (also called Native Accesses).
Used to speed up the browse of data during a simple browse that does not use the following features:
  • Reading the previous record.
  • Modifying a record.
  • Saving position.
If one of these features is used, the result may differ from the expected one.
This constant can be used for example during a browse used to fill a memory Table control.
hKeepFilterThe filter implemented by HFilter will be taken into account, even if the browse key is not optimized for the filter. Reminder: HFilter returns the browse key optimized for the filter.
Caution: In this case, lack of performances may occur on huge data files.
Hyper File 5.5 This variable cannot be used.
hNoRefresh
OLE DBNative Connectors (Native Accesses) HReadLast does not refresh the content of the table or query. The query is not re-run if possible. All the saved positions are stored.
OLE DBNative Connectors (Native Accesses) The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Connector.
OLE DB The lock mode specified by HReadLast will remain effective during the calls to HReadPrevious and HReadNext.
To modify the lock mode, you must use:
Native Connectors (Native Accesses) For Native Oracle Connector, a different lock mode can be specified for each record. However, if a transaction was started by SQLTransaction before implementing the lock, the lock will only be released at the end of the transaction (SQLTransaction associated with SQLCommit or SQLRollBack).
Hyper File 5.5 The lock options are ignored. Use the locking read functions (HReadLastLock) kept for backward compatibility.
PHP The lock options are not available.
Remarks

Read operation according to a key item or not

If the item is a key, HReadLast reads the record with the greatest key value. The sort order is the one that was specified in the analysis for this key. If duplicates are found, HReadLast reads the last "duplicate" record according to the sequence of record numbers.

If the item is not a key, HReadLast reads the last active record. When browsing the data file, the records will be sorted according to their record number.
In this case, the selected search item will appear in red in the code editor and a warning will be displayed in the "Code" pane.
Note: The automatic completion proposes the key items only.
WEBDEV - Server codeAjaxHFSQLHFSQL Client/ServerStored proceduresHyper File 5.5OLE DBNative Connectors (Native Accesses)

Locks

By default (<Options> not specified), no lock operation is performed on the record.
If a lock is requested (hLockWrite or hLockReadWrite constant), the record will be read only if this record is not already locked.
There is no need to specify a lock parameter if the data file is locked by HStartLock: the lock specified by HStartLock is automatically taken into account. To ignore the lock performed by HStartLock, use the hLockNo constant.
OLE DBNative Connectors (Native Accesses) The lock options will have no effect if the locks are not supported by the OLE DB provider or by the Native Connector.

Memos

The memos associated with the record can be automatically read (or not) when reading the record. HSetMemo is used to customize this automatic read operation.
If the memos are supported, the associated text memos are read when the record is read. The binary memos are read only when they are explicitly used (HExtractMemo).
WEBDEV - Server codePHPHFSQLHFSQL Client/ServerStored proceduresHyper File 5.5OLE DBNative Connectors (Native Accesses)

Password

If HReadLast is the first function that handles the specified data file, the password is checked when the data file is opened. If the password is incorrect, HErrorPassword returns True and HOut is set to True.

Various

  • The current record number is returned by HRecNum.
  • HChangeKey is used to modify the search key while being positioned on the current record.
  • To optimize the time of the first browses on a data file, use HOptimize on this data file.
Component : wd240hf.dll
Minimum version required
  • Version 9
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