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Help / WLanguage / Managing databases / HFSQL / HFSQL functions
  • Read operation according to a key
  • Comparison between HNext and HReadNext
  • Miscellaneous
  • Locks
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Stored procedures
Sets the position on the next data file record according to a browse item. The record is not read.
The number of the current Record is changed only when it is returned by the HRecNum function. For the functions handling by default the number of the current Record (functions HDelete, HRead, HModify, ...), the value of this number is not updated: you must use HRecNum(). For example: not to do:
HDelete(Client)
but
HDelete(Client, HRecNum())
get is from the smallest to the largest value of the path heading (see notes for details).
Caution: The record loaded in memory is not modified. The HFSQL variables (Customer.Name for example, which means the Name item of Customer file) are not updated.
In most cases, HNext sets the position in the data file to browse through the records that correspond to a condition. HNext is used to position on the next record corresponding to the condition.
Several cases may occur after the call to HNext:
  • a record corresponding to the condition was found: HFound returns True
  • the data file is empty or there is no record corresponding to the condition: HOut returns True
Remarks:
  • By default, HSeekFirst and HSeekLast are used to perform an exact-match search.
  • By Default, the function HNext performs a generic search.

get is done from the smallest value to the largest value of the path item (see remarks for details).
Caution: The record loaded in memory is not modified. The HFSQL variables (Customer.Name for example, which means the Name item of Customer file) are not updated.
In most cases, HNext is used to position in the data file during a browse loop.
Several cases may occur after the call to HNext:
  • the data file is empty or there is no record corresponding to the filter (defined by function HFilter): function HOut returns True
  • the function tries to lock a record that is already locked in read-only: HErrorLock returns True and HOut returns True.
Example
HFirst(Client, Nom)
WHILE HOut(Client) = False
// Traitement de l'enregistrement
HNext(Client, Nom)
END
Syntax
<Result> = HNext([<Data file> [, <Search key item>] [, <Options>]])
<Result>: Boolean
  • True if the position was set,
  • False if an error occurred. This problem can be caused by:
    • a positioning problem (empty data file, ...): HFound returns False and HError returns 0.
    • an error: HError returns an integer other than 0. HErrorInfo returns more details.
<Data file>: Optional character string
Name of HFSQL data file. If this parameter is an empty string (""), HNext manipulates the last data file used by the last HFSQL function (function starting with "H").
<Search key item>: Optional character string
Name of key item used to browse the data file. If this name is not specified, the HNext function will handle the last path field used on this data file by the last HFSQL management function (function starting with the letter H). If this item does not exist, the best browse item is automatically used.
<Options>: Optional constant
Configures the lock and the management of duplicates performed on the record selected by HNext:
hLockWriteLock in write mode: the selected record can be read by another application but it cannot be modified by another application.
hLockReadWriteLock in read/write: the selected record cannot be read or modified by another application.
OLE DB Lock in write-only: the record currently read can be read by another application but it cannot be modified by another application.
Operating mode equivalent to the one of hLockWrite.
hLockNoNo lock: the record can be read or modified by another application.
hDistinctIf duplicates are found, it is used to position on a single record among the duplicates. This parameter is taken into account only if the browse is performed on a key item.
By default, all the duplicates are browsed.
OLE DBNative Connectors (Native Accesses) This constant is ignored.
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 Native Access.
OLE DB The lock mode specified by HReadFirst will remain effective during the calls to HReadPrevious and HReadNext.
To modify the lock mode, you must use:
Hyper File 5.5 The lock options are ignored. Use the lock functions (HLockRecNum) kept for backward compatibility.
Remarks

Read operation according to a key

HNext positions on the next record with the greatest key value. The sort order is the one that was specified in the analysis for this key.

Comparison between HNext and HReadNext

HNext does not read the record: therefore, HNext is faster than HReadNext.

Miscellaneous

  • The current record number is returned by HRecNum.
  • The HChangeKey function allows you to change the route key, while remaining positioned on the current Record.
WEBDEV - Server codeAjaxHFSQLHFSQL Client/ServerHyper File 5.5OLE DBNative Connectors (Native Accesses)

Locks

By default (<Options> not specified), the record is not locked.
If a lock is requested (hLockWrite or hLockReadWrite constant), the position will be set on the record only if it is not already locked.
Component: wd270hf.dll
Minimum version required
  • Version 9
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Last update: 12/14/2023

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