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  • Syntax 2: Performing a transaction on a connection
  • Nesting transactions
  • Locks and transactions
  • Native MySQL Connector
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Stored procedures
SQLTransaction (Function)
In french: SQLTransaction
Begins, commits or rolls back a transaction:
  • on the files of a database opened by SQLConnect,
  • on the files of a database opened by a connection (OLE DB or Native Access/Native Connector) described in the data model editor or by HOpenConnection.
Remark: This function is the only SQL function that can be used with the HFSQL functions (to perform transactions on an external database handled by the HFSQL functions for example). Remark: From version 19, HFSQL is the new name of HyperFileSQL.
Reports and QueriesOLE DB
ConnectionNum is int = SQLConnect("MyDatabase", "User", "Password", "", ...
"OLEDB", "MyProvider")
IF ConnectionNum = 0 THEN
SQLInfo()
Error("Error while opening the connection: " + SQL.MesError)
ELSE
// Put the connection in transaction
SQLTransaction(sqlStart)
// Modify the value of all the AFile.AnItem items
IF SQLExec("UPDATE AFile SET AnItem = 'new value", ...
"UpdateQuery") = True THEN
// End the transaction
SQLTransaction(sqlCommit)
ELSE
SQLInfo("UpdateQuery")
Error("Error while running the query: " + SQL.MesError)
// Cancel the transaction
SQLTransaction(sqlRollBack)
// The content of AFile did not change
END
END
Syntax

Transaction on the files of a database opened by SQLConnect Hide the details

<Result> = SQLTransaction(<Indicator>)
<Result>: Boolean
  • True if the operation was performed,
  • False otherwise.
<Indicator>: Integer constant
Type of transaction operation to perform:
sqlStartStarts the transaction.
sqlCommitEnd the transaction.
sqlRollBackCancels the transaction.
Remark: This syntax is not available in Android.
Reports and Queries

Transaction on the files of a database opened by a connection described in the analysis or by HOpenConnection Hide the details

<Result> = SQLTransaction(<Indicator> , <Connection>)
<Result>: Boolean
  • True if the operation was performed,
  • False otherwise.
<Indicator>: Integer constant
Type of transaction operation to perform:
sqlStartStarts the transaction.
sqlCommitEnd the transaction.
sqlRollBackCancels the transaction.
<Connection>: Character string
Name of connection used to access the database. This name was defined in the data model editor or by HOpenConnection. This connection must have been described during the call to SQLTransaction. If the connection is not opened during the call to SQLTransaction, the specified connection is automatically opened.
Remarks

Syntax 2: Performing a transaction on a connection

To perform a transaction on a connection, you must:
  1. Start the connection (SQLTransaction(sqlStart)).
  2. Perform the operations on the data files with the relevant HFSQL functions.
  3. End the transaction:
    • by validating the operations performed (SQLTransaction(sqlCommit)).
    • by canceling the operations performed (SQLTransaction(sqlRollBack)).

Nesting transactions

Transactions can be nested.

Locks and transactions

SQLTransaction does not lock data files or records. SQLTransaction begins, commits or rolls back a transaction.
If a transaction is started:
  • write operations in tables can cause deadlocks (e.g. in an HFSQL database, write operations lock records).
  • read operations can cause deadlocks on some databases if the isolation level is "repeatable-read" or "serializable" (note that this is not the case in HFSQL databases).
Reports and QueriesNative Connectors (Native Accesses)

Native MySQL Connector

SQLLock and SQLTransaction are used to to manage locks and transactions only on "innoDB" MySQL tables.
Component: wd270hf.dll
Minimum version required
  • Version 9
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