<Connection variable>.TransactionStart (Function)

ONLINE HELP
WINDEV, WEBDEV AND WINDEV MOBILE

Version:

Home | Sign in | English

Locking records
Error cases
Handling records during a transaction
Transactions and independent HFSQL context
OLE DB and Native Connectors

WINDEV

WEBDEV

WINDEV Mobile

Others

See also

<Connection variable>.TransactionStart (Function)

In french: <Variable Connexion>.TransactionDébut

Not available with this kind of connection

Starts a transaction on the data files (HFSQL or accessed via a Native Connector) and creates the transaction file.

What information is saved in the transaction file? Whenever a WLanguage function modifies a data file or an index file during a transaction, the former values of the record and the operation performed are stored in the transaction file.

Versions 19 and later
The transaction can be started on a connection: In this case, a transaction is started only for files associated to this connection. This mode is required to manage the isolation levels of transactions.

New in version 19
The transaction can be started on a connection: In this case, a transaction is started only for files associated to this connection. This mode is required to manage the isolation levels of transactions.

The transaction can be started on a connection: In this case, a transaction is started only for files associated to this connection. This mode is required to manage the isolation levels of transactions.

Versions 18 and later

This function is now available in Windows Store apps mode.

This function is now available for Java applications.

New in version 18

This function is now available in Windows Store apps mode.

This function is now available for Java applications.

This function is now available in Windows Store apps mode.

This function is now available for Java applications.

Remark: From version 19, HFSQL is the new name of HyperFileSQL.

Versions 21 and later

This function is now available in Universal Windows 10 App mode.

New in version 21

This function is now available in Universal Windows 10 App mode.

Versions 23 and later
Remark: This function is equivalent to <Connection variable>.Transaction.

New in version 23
Remark: This function is equivalent to <Connection variable>.Transaction.

Remark: This function is equivalent to <Connection variable>.Transaction.

Example

MyConnection1 is Connection

// Start transaction on data files associated with MyConnection1
MyConnection1.TransactionStart()

// Code used to prepare the order to added
// ...

WHEN EXCEPTION IN
// Add the order
Order.Add()
// Validate the addition
MyConnection1.TransactionEnd()
DO
// Delete the order lines
MyConnection1.TransactionCancel()
END

Syntax

Starting a Client/Server transaction on a specific connection Hide the details

<Result> = <Connection>.TransactionStart([<List of data files>])

<Result>: Boolean

True if the transaction was started,
False if a problem occurred. HErrorInfo returns more details about the error.

<Connection>: Connection variable

Name of the Connection variable that describes the connection to use.

<List of data files>: Optional character string (with quotes)

List of logical names of one or more data files to take into account (or not) in the transaction (in this case, the data file name is preceded by the "-" sign).
If this parameter is not specified All data files used during the transaction will be taken into account in the transaction.
If all data files are prefixed with the "-" sign
For example: "-Customer, -Product" All data files specified in the list and used during the transaction will not be taken into account by the transaction.
All data files not specified in the list will be taken into account and used during the transaction.
If no data file on the list is prefixed with the "-" sign
For example: "Customer, Product" All data files specified in the list and used during the transaction will be taken into account in the transaction.
All data files not specified and manipulated during the transaction will be ignored in the transaction.
If some data files are prefixed with "-" and others are not
For example: "-Customer, Product" (equivalent to "Product") All data files in the list prefixed with "-" and used during the transaction will be ignored in the transaction.
All data files in the list not prefixed with "-" and used during the transaction will be taken into account in the transaction.
The files not specified in the list will be excluded from the transaction.
This parameter is ignored. All the data files associated with the connection are in transaction on the native server.

Starting a Client/Server transaction on a specific connection Hide the details

<Result> = <Connection>.TransactionStart(<Transaction file> , <List of data files>)

<Result>: Boolean

True if the transaction was started,
False if a problem occurred. HErrorInfo returns more details about the error.

<Connection>: Connection variable

Name of the Connection variable that describes the connection to use.

<Transaction file>: Character string (with quotes)

Full name of transaction file (used to store the operations performed in transaction).
This parameter is not taken into account for connections to an HFSQL Server.

<List of data files>: Character string (with quotes)

List of logical names of one or more data files to take into account (or not) in the transaction (in this case, the data file name is preceded by the "-" sign).
If this parameter is not specified All data files used during the transaction will be taken into account in the transaction.
If all data files are prefixed with the "-" sign
For example: "-Customer, -Product" All data files specified in the list and used during the transaction will not be taken into account by the transaction.
All data files not specified in the list will be taken into account and used during the transaction.
If no data file on the list is prefixed with the "-" sign
For example: "Customer, Product" All data files specified in the list and used during the transaction will be taken into account in the transaction.
All data files not specified and manipulated during the transaction will be ignored in the transaction.
If some data files are prefixed with "-" and others are not
For example: "-Customer, Product" (equivalent to "Product") All data files in the list prefixed with "-" and used during the transaction will be ignored in the transaction.
All data files in the list not prefixed with "-" and used during the transaction will be taken into account in the transaction.
Data files not specified in the list will be excluded from the transaction.
This parameter is ignored. All the data files associated with the connection are in transaction on the native server.

Remarks

Locking records

The added, modified or deleted records in a transaction are locked in write mode.

Error cases

Nesting transactions: Transactions cannot be nested (i.e. <Connection variable>.TransactionStart cannot be called in a transaction). In this case, error 70031 occurs.
Versions 19 and later
A fatal error is displayed in the following cases:
- A transaction is started on all the connections while there is at least one connection in transaction.
- A transaction is started on a connection while a transaction was already started on all the connections.
- A transaction is started on all the connections while there is at least one connection whose isolation mode is not "Read Uncommitted".
New in version 19
A fatal error is displayed in the following cases:
- A transaction is started on all the connections while there is at least one connection in transaction.
- A transaction is started on a connection while a transaction was already started on all the connections.
- A transaction is started on all the connections while there is at least one connection whose isolation mode is not "Read Uncommitted".
A fatal error is displayed in the following cases:
- A transaction is started on all the connections while there is at least one connection in transaction.
- A transaction is started on a connection while a transaction was already started on all the connections.
- A transaction is started on all the connections while there is at least one connection whose isolation mode is not "Read Uncommitted".

Handling records during a transaction

During a transaction, some rules must be complied with when handling the records. For more details, see Transactions: Handling records during a transaction.

Transactions and independent HFSQL context

When copying a context, if a transaction is in progress on the first context, the new context is not in transaction. You must call <Connection variable>.TransactionStart to start a transaction in the new context.

OLE DB and Native Connectors

<Connection variable>.TransactionStart cannot be used in this version. To start a transaction, use SQLTransaction.Only the syntaxes with connection are taken into account by the Native Accesses that support the transactions. You can also use SQLTransaction.

Component: wd260hf.dll