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  • Read operation based on a key
  • Password verification
  • Miscellaneous
  • Comparison between .ReadFirst and <Source>.First
  • Locks
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Stored procedures
Positions on the first Record of a data file according to the specified route item. The record is not read.
The number of the current record is modified only when it is returned by <Source>.RecNum. For the functions that handle the current record number (<Source>.Delete, <Source>.Read, <Source>.Modify, etc.), the value of this number is not updated: you must use <Source>.RecNum(). For example: not to do:
Customer.Delete()
but
Customer.Delete(Customer.RecNum())
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, <Source>.First sets the position in the data file to loop through the records that match a condition. <Source>.Next is used to position on the next record corresponding to the condition.
Several cases may occur after the call to <Source>.First:
  • a record corresponding to the condition was found: <Source>.Found returns True
  • the data file is empty or there is no record corresponding to the condition: <Source>.Out returns True
Remarks:

Values in the browse item are read in ascending order (for more details, see the the remarks).
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, <Source>.First is used to set the position in the data file in order to perform a read loop with <Source>.Next.
Several cases may occur after the call to <Source>.First:
  • the data file is empty or no record corresponds to the filter (defined by <Source>.Filter): <Source>.Out returns True.
  • the function tries to lock a record that is already locked in read-only: HErrorLock returns True and <Source>.Out returns True.
    Java Access by JDBC: Locks cannot be managed in databases accessed by JDBC.
Example
Customer.First(Name)
WHILE Customer.Out() = False
// Process the record
Customer.Next(Name)
END
Syntax
<Result> = <Source>.First([<Search key item> [, <Options>]])
<Result>: Boolean
  • True if the position was set,
  • False if an error occurs. This problem can be caused by:
<Source>: Type corresponding to the specified source
Name of the data file used.
<Search key item>: Optional character string
Name of the key item used to loop through the data file. If this name is not specified, <Source>.First 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 set on the record selected by <Source>.First:
hKeepFilterThe filter set by <Source>.Filter will be taken into account, even if the search key is not optimized for the filter. Reminder: <Source>.Filter returns the search key optimized for the filter.
Caution: In this case, performance issues may arise for large data files.
Hyper File 5.5 This variable cannot be used.
hLockNoNo lock: the record can be read or modified by another application.
Java Access by JDBC: This constant is not available.
hLockReadWriteLock in read/write mode: the selected record cannot be read or modified by another application.
OLE DB Lock in write mode: the selected record can be read by another application but it cannot be modified. Equivalent to hLockWrite.

Java Access by JDBC: This constant is not available.
hLockWriteLock in write mode: the selected record can be read by another application but it cannot be modified.
Java Access by JDBC: This constant is not available.
hNoRefresh
OLE DB The table or query content will not be refreshed. All the saved positions are stored. If this parameter is not specified, <Source>.First reinitializes the browse for the specified item: the content of table or query is refreshed with the data found in the OLE DB database. All the saved positions are lost. The position will be restored according to the value of best item.
Remark: The browses and the positions saved on the other items are not affected.
Java Access by JDBC: Locks cannot be managed in databases accessed by JDBC.
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 the Native Connector.
OLE DB The lock mode specified by <Source>.First will remain effective during the calls to <Source>.Previous and <Source>.Next.
To change the lock mode, use:
Native Connectors (Native Accesses) Oracle: a different lock mode can be specified for each record. However, if a transaction was started by SQLTransaction before setting the lock, the lock will only be released at the end of the transaction (SQLTransaction associated with sqlCommit or sqlRollback).
Hyper File 5.5 The lock options are ignored. Use the lock functions (<Source>.LockRecNum) kept for backward compatibility.
Remarks

Read operation based on a key

<Source>.First positions on the record with the smallest key value.
The sort order taken into account is the one specified in the analysis for this key.
If duplicates are found, <Source>.First sets the position on the first "duplicate" record according to the sequence of record numbers.
WINDEVWEBDEV - Server codeReports and QueriesUniversal Windows 10 AppiPhone/iPadJavaUser code (UMC)AjaxHFSQL ClassicHFSQL Client/ServerHyper File 5.5

Password verification

If <Source>.First is the first function that handles the specified data file, the password is checked when opening the data file.
If the password is incorrect, HErrorPassword returns True and <Source>.Out returns True.

Miscellaneous

Comparison between <Source>.ReadFirst and <Source>.First

<Source>.First does not read the record: therefore, <Source>.First is faster than <Source>.ReadFirst.
WINDEVWEBDEV - Server codeWINDEV MobileReports and QueriesUniversal Windows 10 AppiPhone/iPadUser code (UMC)AjaxHFSQL ClassicHFSQL 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: wd290hf.dll
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  • Version 25
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Last update: 07/06/2023

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