tx

API Reference

Module tx

The tx module brings a simple API to use database transactions.

This API is inspired by the old Web SQL API.

queueTransaction(client, transactionCallback, resultCallback)

• client: a node-pg client (usually acquired by pg.connect())
• transactionCallback: a callback to run the transaction. The signature is transactionCallback(transaction). transaction is a transaction object used to execute SQL statements.
• resultCallback: a callback to be invoked directly after committing or revoking the transaction. The signature is resultCallback(error). If error is not null it is the error that triggered the rollback.

Queue a transaction for execution.

Transaction

executeSql(statement, parameters, callback)

• statement: The SQL statement to be executed.
• parameters (optional): Parameters for the SQL query.
• callback (optional): A callback to be invoked directly after executing the SQL statement. The signature is callback(error, resultSet). error will be set if there was a problem. If the error is null, resultSet will contain the result of your query.

Queue the execution of statement with parameters. Invoke callback after the execution. You can use the callback to execute more SQL statements.

Example

var pg = require('pg');
var tx = require('tx');

var connectionInfo = require('./connection-info.json');

pg.connect(connectionInfo, function (error, client) {
    if (error) {
        throw error;
    }
    
    tx.queueTransaction(client, function (transaction) {
        transaction.executeSql("CREATE TABLE \"myTable\" " +
                               "(id SERIAL PRIMARY KEY, name CHAR(255) NOT NULL)");
        transaction.executeSql("INSERT INTO \"myTable\" (name) VALUES ('some name')");
        transaction.executeSql("INSERT INTO \"myTable\" (name) VALUES ($1)", ['other name']);
        transaction.executeSql("INSERT INTO \"myTable\" (name) VALUES ('another name') RETURNING id", function (error, resultSet) {
            if (!error) {
            	console.log('insert result: %j', resultSet);
            }
        });
        transaction.executeSql("INSERT INTO \"myTable\" (name) VALUES ($1) RETURNING id", ['yet another name'], function (error, result) {
        	if (!error) {
        		console.log('insert result: %j', resultSet);
        	}
        });
    }, function (error) {
        if (error) {
            // the transaction failed and was rolled back
            throw error;
        }
        
        // the transaction passed
    });
});