Positions on next file record according to a search item. The record is not read.
The number of the current record is only changed when it is returned by the HRecNum
function. For functions that manipulate by default the number of the current record (functions HDelete
,...), the value of this number is not updated: you must use HRecNum
(). For example: not to do:
The reading is performed from the lowest value to the greatest value of the browse item (see remarks
for more 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:
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
- the data file is empty or no record corresponds to the filter (defined by HFilter): HOut returns True
- the function tries to lock a record that is already locked in read-only: HErrorLock returns True and HOut returns True.
WHILE HOut(Customer) = False
// Process the record
<Result> = HNext([<Data file> [, <Search key item>] [, <Options>]])
- True if the positioning was performed,
- 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 (with or without quotes)
Name of HFSQL data file. If this parameter corresponds to an empty string (""), HNext uses the last data file used by the last HFSQL management function (function starting with "H").
<Search key item>: Optional character string (with or without quotes)
Name of key item used to browse the data file. If this name is not specified, HNext handles the last search item used on this data 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.
<Options>: Optional constant
Configures the lock and the management of duplicates performed on the record selected by HNext:
|hLockWrite||Lock in write mode: the selected record can be read by another application but it cannot be modified by another application.|
|hLockReadWrite||Lock in read/write: the selected record cannot be read or modified by another application.|
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
|hLockNo||No lock (even if HStartLock was called): the record can be read or modified by another application.|
|hDistinct||If 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.
This constant is ignored.
The lock options will have no effect if the locks are not supported by the OLE DB provider or by Native Access.
To modify the lock mode, you must use:
The lock options are ignored. Use the lock functions (HLockRecNum
) kept for backward compatibility.
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 of HNext and HLitSuivant
The function HNext
does not read the record: therefore, HNext
is faster than HReadNext
- The current record number is returned by HRecNum.
- The HChangeKey function allows you to modify the route key, while remaining positioned on the current record.
By default (<Options> not specified), no lock operation is performed on the record.
If a lock is requested (hLockWrite or hLockReadWrite constant), the positioning on the record will be performed 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. If you do not want to take into account the blocking performed by the HStartLock
function, use the hBlockNot