<Source>.Flush (Function)

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Managing locks
.Security and <Source>.Flush

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<Source>.Flush (Function)

In french: <Source>.ForceEcriture

Available 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, ...).

Remark: 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).

This function is available for HFSQL data files only. It is not available for the data files accessed by JDBC.

Example

// Add a record in a data file
// (record described through programming)
Customer.LastName = "Clark"
Customer.FirstName = "Vince"
Customer.Address = "Palm lane"
Customer.City = "San Francisco"
Customer.Zip = "94102"
Customer.Country = "USA"
Customer.Add()
// Forces a write operation into Customer file
Customer.Flush()

Syntax

<Source>.Flush()

<Source>: Type corresponding to the specified source

Name of the data file used.

Remarks

Managing locks

During the call to <Source>.Flush, 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.

Remark: 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.

<Source>.Security and <Source>.Flush

<Source>.Security and <Source>.Flush can both be used to force a physical write operation on disk.

However:

<Source>.Security is used to force a write operation into the data files used during each write operation. The HFSQL engine automatically performs the write operation. The data files are not closed during this write operation. This results in slower write speeds.
<Source>.Flush forces the data file(s) to be written when it is called. The data files are closed and then re-opened during this write operation. The write operation is not slowed down.

Component: wd300hf.dll