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  • Managing locks
  • HSecurity and HFlush functions
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Stored procedures
HFlush (Function)
In French: HForceEcriture
HFSQLHFSQL Client/ServerAvailable only with these kinds of connection
Forces the operating system of the computer where the data files are found to write data onto the disk. The HFSQL context of the data file used is stored (lock, current browse, ...).
Note: Used on a regular basis, this function minimizes the loss of data caused by the unexpected system outage on the computer where the data files are located (power failure for example).
Versions 16 and later
WINDEVJava This function is now available for the Java applications.
Java This function is available for the HFSQL data files only. It is not available for the data files accessed by JDBC.
New in version 16
WINDEVJava This function is now available for the Java applications.
Java This function is available for the HFSQL data files only. It is not available for the data files accessed by JDBC.
WINDEVJava This function is now available for the Java applications.
Java This function is available for the HFSQL data files only. It is not available for the data files accessed by JDBC.
Versions 18 and later
Android Widget This function is now available in Android Widget mode.
Android This function is now available for the Android applications (for the HFSQL data files).
Universal Windows 10 App This function is now available in Windows Store apps mode.
iPhone/iPad This function is now available for the iPhone/iPad applications.
New in version 18
Android Widget This function is now available in Android Widget mode.
Android This function is now available for the Android applications (for the HFSQL data files).
Universal Windows 10 App This function is now available in Windows Store apps mode.
iPhone/iPad This function is now available for the iPhone/iPad applications.
Android Widget This function is now available in Android Widget mode.
Android This function is now available for the Android applications (for the HFSQL data files).
Universal Windows 10 App This function is now available in Windows Store apps mode.
iPhone/iPad This function is now available for the iPhone/iPad applications.
Versions 21 and later
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
New in version 21
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Universal Windows 10 App This function is now available in Universal Windows 10 App mode.
Note: From version 19, HFSQL is the new name of HyperFileSQL.
Example
// Add a record into a file
// (record described by programming)
Customer.LastName = "Clark"
Customer.FirstName = "Vince"
Customer.Address = "Palm lane"
Customer.City = "San Francisco"
Customer.Zip = "94102"
Customer.Country = "USA"
HAdd(Customer)
// Forces a write operation into Customer file
HFlush(Customer)
Syntax
HFlush(<File Name>)
<File Name>: Character string (with or without quotes)
Name of data file used.
If this name is not specified, HFlush handles the last data file used by the last function for HFSQL management (starting with the letter H).
If this parameter corresponds to "*", HFlush will be applied to all opened data files.
Caution: In this case, the execution of function can be quite long.
This parameter can also correspond to the name of a group of files (or custom-folder) defined in the analysis.
Remarks
WINDEVWEBDEV - Server codeReports and QueriesiPhone/iPadWindows MobileUniversal Windows 10 AppAjaxUser code (UMC)HFSQLHFSQL Client/Server

Managing locks

During the call to HFlush, the data file used is closed and re-opened. If locks were implemented on this data file before it was closed, these locks are automatically restored when it is re-opened. Indeed, when closing a data file, the operating system deletes the locks implemented on this data file.
Note: It is not advisable to call this function too often on:
  • data files on which an important number of locks is implemented.
  • data files on which an important number of write operations is implemented.

HSecurity and HFlush functions

HSecurity and HFlush can both be used to force a physical write operation on disk.
However:
  • HSecurity is used to force a write operation into the data files used during each write operation. This write operation is automatically performed by the HFSQL engine. The data files used are not closed during this write operation. The speed of the write-to-file operation is slower.
  • HFlush is used to force a write operation into the data files used during the call to this function. The data files used are closed then re-opened during this write operation. The speed of the write-to-file operation is not slowed down.
Components
WINDEVWEBDEV - Server codeReports and Queries wd230hf.dll
Windows Mobile wp230hf.dll
Java wd230java.jar
Linux wd230hf.so
Android wd230android.jar
Minimum required version
  • Version 9
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