- Read operation according to a key item or not
- Browsing the records corresponding to a condition
- Locks
- Memos
- Various
<Source>.ReadPrevious (Function) In french: <Source>.LitPrécédent
 Not available with this kind of connection
Positions on the previous file record according to a browse item. The record is read and the HFSQL variables are updated (Customer.Name for example, which means the Name item of Customer file). The reading is performed from the greatest value to the lowest value of search item (see remarks for more details). In most cases, <Source>.ReadPrevious is used to position in the data file during a browse loop. Several cases may occur after the call to <Source>.ReadPrevious: - the data file is empty or there is no record corresponding to the filter (defined by <Source>.Filter): no reading is performed and <Source>.Out returns True.
- the function tries to lock a record that is already locked in read-only: no reading is performed, HErrorLock returns True and <Source>.Out returns True.
 The management of locks is only performed on HFSQL Client/Server data files or data files handled by a 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 databases accessed by JDBC.
Customer.ReadLast(Name)
WHILE Customer.Out() = False
// Process the record
Customer.ReadPrevious(Name)
END
Syntax
<Result> = <Source>.ReadPrevious([<Browse item> [, <Options>]])
<Result>: Boolean - True if the previous record was read,
- False if an error occurred (lock, end of data file, etc.): the record is not read. This problem can be caused by:
<Source>: Type corresponding to the specified source Name of data file, HFSQL view or query used. <Browse item>: Optional character string (with or without quotes) Name of item used to browse the data file. If this name is not specified, <Source>.ReadPrevious 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 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) Used to configure:- the lock performed on the record read by <Source>.ReadPrevious.
- the management of duplicates. By default, all the duplicates are browsed.
| | | 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. | | hDistinct | If duplicates are found, this constant allows you to read a single record among the duplicates. This parameter is taken into account only if the browse is performed on a key item. |
Remarks Read operation according to a key item or not If the item is a key, <Source>.ReadPrevious reads the record with the greatest key value. The sort order is the one that was specified in the analysis for this key.
If the item is not a key, <Source>.ReadPrevious reads the previous 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. Browsing the records corresponding to a condition - if the item is a key, <Source>.ReadPrevious reads the previous records corresponding to the values less than or equal to the sought value.
- if the item used is not a key, <Source>.ReadPrevious will read the next records corresponding to the values equal to the sought value.
To ignore the search while going to the next or previous record, use one of the following functions: Memos The memos associated with the record can be automatically read (or not) when reading the record. <Source>.SetMemo 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 ( <Source>.ExtractMemo).
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