- Read operation according to a key item or not
- Locks
- Memos
- Password
- Various
HReadLast (Function) In french: HLitDernier
 Not available with this kind of connection
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.
 Locks are managed only on HFSQL Client/Server data files or on data files handled by a Native Connector (also called Native Access). An HFSQL Mobile record cannot be locked. Indeed, the operating system of Pocket PC does not allow you to lock records.
 The management of locks is not available.
 Access by JDBC: The management of locks is not available for the databases accessed by JDBC.
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.
| | | hLockNo | No lock (even if HStartLock was called): the record can be read or modified by another application during the reading.
| | hLockWrite | Lock in write mode: the record currently read can be read by another application but it cannot be modified by another application.
| | hLockReadWrite | Lock in read/write: the record currently read cannot be read or modified by another application.
|  Versions 17 and laterhForwardOnly New in version 17hForwardOnly | | | hKeepFilter | The 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.
| | hNoRefresh | |
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. 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). 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.
This page is also available for…
|
|
|