Transaction interface

Transaction API. More...

Functions
struct evsql_trans *	evsql_trans (struct evsql *evsql, enum evsql_trans_type type, evsql_trans_error_cb error_fn, evsql_trans_ready_cb ready_fn, evsql_trans_done_cb done_fn, void *cb_arg)
	Create a new transaction.
int	evsql_trans_commit (struct evsql_trans *trans)
	Commit a transaction using "COMMIT TRANSACTION".
void	evsql_trans_abort (struct evsql_trans *trans)
	Abort a transaction, using "ROLLBACK TRANSACTION".
const char *	evsql_trans_error (struct evsql_trans *trans)
	Retrieve the transaction-specific error message from the underlying engine.

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Detailed Description

Transaction API.

See also:

evsql.h

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Function Documentation

struct evsql_trans* evsql_trans	(	struct evsql *	evsql,
		enum evsql_trans_type	type,
		evsql_trans_error_cb	error_fn,
		evsql_trans_ready_cb	ready_fn,
		evsql_trans_done_cb	done_fn,
		void *	cb_arg
	)			[read]

Create a new transaction.

A transaction will be allocated its own connection, and the "BEGIN TRANSACTION ..." query will be sent (use the type argument to specify this).

Once the transaction has been opened, the given ready_fn will be triggered, and the transaction can then be used (see Query interface).

If, at any point, the transaction-connection fails, any pending query will be forgotten (i.e. the query callback will NOT be called), and the given error_fn will be called. Note that this includes some, but not all, cases where Query interface returns an error.

Once you are done with the transaction, call either evsql_trans_commit() or evsql_trans_abort().

Parameters:

	evsql	the context handle from Session creation interface
	type	the type of transaction to create
	error_fn	the evsql_trans_error_cb() to call if this transaction fails
	ready_fn	the evsql_trans_ready_cb() to call once this transaction is ready for use
	done_fn	the evsql_trans_done_cb() to call once this transaction has been commmited
	cb_arg	the void* to pass to the above

Returns:

the evsql_trans handle for use with other functions

void evsql_trans_abort

(

struct evsql_trans *

trans

)

Abort a transaction, using "ROLLBACK TRANSACTION".

No more transaction callbacks will be called. If there was a query running, it will be aborted, and the transaction then rollback'd.

You cannot abort a COMMIT, calling trans_abort on trans after a call to trans_commit is an error.

Do not call evsql_trans_abort from within evsql_trans_error_cb()!

Parameters:

trans

the transaction from evsql_trans to abort

See also:

evsql_trans

int evsql_trans_commit

(

struct evsql_trans *

trans

)

Commit a transaction using "COMMIT TRANSACTION".

The transaction must be idle, just like for evsql_query. Once the transaction has been commited, the transaction's done_fn will be called, after which the transaction must not be used anymore.

You cannot abort a COMMIT, calling trans_abort() on trans after a succesful trans_commit is an error.

Note that done_fn will never be called directly, always indirectly via the event loop.

Parameters:

trans

the transaction handle from evsql_trans to commit

See also:

evsql_trans

const char* evsql_trans_error

(

struct evsql_trans *

trans

)

Retrieve the transaction-specific error message from the underlying engine.

Intended to be called from evsql_trans_error_cb()