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- Read operation based on a key
- Comparison between HNext and HReadNext
- Miscellaneous
- Locks
HNext (Function) In french: HSuivant
 Not available with this kind of connection
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 modified only when it is returned by HRecNum. For the functions that handle the current record number ( HDelete, HRead, HModify, etc.), the value of this number is not updated: you must use HRecNum(). For example: not to do:
but
HDelete(Customer, HRecNum())
Values in the browse item are read in ascending order (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 sets the position in the data file to loop through the records that match 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, HNext performs a generic search.
Values in the browse item are read in ascending order (for more details, see the remarks). Caution: The record loaded in memory is not modified. The HFSQL variables (for example Customer.Name, i.e. the Name item of the Customer file) are not updated. Generally, HNext sets the position in the data file during a loop operation. Several cases may occur after the call to HNext: - 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.
 Access by JDBC: Locks cannot be managed in databases accessed by JDBC.
HFirst(Customer, Name)
WHILE HOut(Customer) = False
HNext(Customer, Name)
END
Syntax
<Result> = HNext([<Data file> [, <Search key item>] [, <Options>]])
<Result>: Boolean - True if the position was set,
- False if an error occurs. This problem can be caused by:
- a positioning problem (empty data file, etc.): 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 the 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 the key item used to loop through the data file. If this name is not specified, HNext will use the last browse item used on this data file by the last HFSQL management function (function starting with "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: | | | hDistinct | If there are any duplicates, sets the position on a single record of the duplicates. This parameter is taken into account only if the iteration is performed on a key item.
By default, all duplicates are iterated over.
| | hLockNo | No lock: the record can be read or modified by another application. | | hLockReadWrite | Lock in read/write mode: the selected record cannot be read or modified by another application. | | hLockWrite | Lock in write mode: the selected record can be read by another application but it cannot be modified. |
To change the lock mode, use: Remarks Read operation based on a key HNext positions on the next record with the greatest key value. The sort order taken into account is the one 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 - HRecNum returns the current record number.
- HChangeKey changes the search key while keeping the position on the current record.
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