Insert transaction

A transaction is a group of SQL statements whose effects are logically connected. Anything from simple queries to inserting, and deleting operations can be considered a transaction, as well as more complex groups of several statements which accomplish a specific task.

A database refers to data organized and stored on a computer that can be searched and retrieved by a computer program. Most industrial-strength and many smaller database applications can be addressed using SQL (Structured Query Language).

A query is a SQL command that will extract information from the tables of a database. Essentially, a query is a request for information from your database.

A dispatcher is a component of the Transaction Engine which contains all the transactions on a page and handles all interactions between that page and the transactions: executes the transactions, feeds the recordsets generated by the transactions to the page, displays the transaction's error messages, etc.

A trigger is a SQL procedure that performs an action when a transaction (INSERT, UPDATE, DELETE) occurs. You can use triggers to perform validation of input data, to automatically generate a value for a newly inserted row, to read from other tables for cross-referencing purposes, or to support alerts through e-mail messages.

A primary key is one or more table columns whose values uniquely identify each record in a table. In general, a primary key is defined on a single column, but it is not uncommon to have it defined on two columns.

A recordset is the result of executing an SQL query. It is composed of multiple rows, each row having multiple columns. The columns presented in the query result depend on the column list declared in the query (they can belong to different tables). The number of rows and their order depend on the query conditions (WHERE, GROUP BY, HAVING, ORDER). The recordset acts as a source of dynamic data in web applications.

The InterAKT Dynamic Data tool is a replacement for the standard dynamic data dialog. It is used in the MX Kollection 3, to provide a unified way of building mark-ups, or place holders. These are recordset fields, server or session variables, and other types of dynamic data that are replaced at runtime by their corresponding values

Insert transaction

A typical insert transaction uses code like the snippet below, to achieve its purpose: inserting a set of values into a database table.

The first thing that occurs when adding a new transaction into a page is the inclusion of the Transaction Engine 3 classes. They are included in a file called tNG.inc.php, in the includes/tng folder on the server. This folder is created automatically when using a Transaction Engine 3 feature in one of the site's pages:

// Load the Transaction Engine 3 classes
require_once('includes/tng/tNG.inc.php');

As you can have multiple transactions on page, each one must register with the page's unique dispatcher, so that it can establish a coherent order of execution. In order to create a new dispatcher, the generated code creates a new instance of the dispatcher object, passing it as parameter the file's path relative to the site root (e.g. for a file in the /files folder, the path is ../):

// Make a transaction dispatcher instance
$tNGs = new tNG_dispatcher("");

The standard connection is transformed into a Transaction Engine 3 connection and made available through a variable:

// Make unified connection variable
$conn_localhost = new tNG_connection($localhost, $database_localhost);

The triggers for this page are now created. For form validations, the tNG_FormValidation trigger is used.

The fields that are required for validation will be added using the addField method. If the field does not require any validation, it will not be added to the tNG_FormValidation object. After the fields are added, the Dispatcher is instructed to prepare the validation:

// Start trigger
$formValidation = new tNG_FormValidation($tNGs);
$tNGs->prepareValidation($formValidation);
// End trigger

This code section creates the actual transaction type: an insert one. As you can see, all is done OOP; creating a new insert transaction resumes to instantiating a class. Aside creating the transaction, it is also registered to the dispatcher, by the addTransaction method, that takes the name of the transaction as a parameter:

// Make an insert transaction instance
$ins_company_com = new tNG_insert($conn_localhost);
$tNGs->addTransaction($ins_company_com);

To add Triggers to the Transaction, the tNG->registerTrigger() method is used. The first three parameters are required, (Trigger type, Trigger name, Trigger priority), and the last are optional and represent the parameters used by the Transaction to call the Trigger. Besides these extra parameters, the first parameter always passed when calling a Trigger is the reference to the instance of the current executing Transaction. In this way, the trigger has access to the Transaction context:

// Register triggers
$ins_company_com->registerTrigger("STARTER", "Trigger_Default_Starter", 1, "POST", "MM_Insert1");
$ins_company_com->registerTrigger("BEFORE", "Trigger_Default_FormValidation", 10, $formValidation);
$ins_company_com->registerTrigger("END", "Trigger_Default_Redirect", 99, index.php);

For example, in this case, the transaction will execute the trigger Trigger_Default_Redirect like this:

Trigger_Default_Redirect($this,"index.php");

The next section of code assigns the table into which the insert will occur (in the first line) and then adds the actual columns to the table. The last line defines the primary key of the table: the field name, and its type. When adding a column, the arguments passed to the addColumn method are: the column name, column type, method of passing the value, reference and default value:

// Add columns
$ins_company_com->setTable("company_com");
$ins_company_com->addColumn("name_com", "STRING_TYPE", "POST", "name_com");
$ins_company_com->addColumn("address_com", "STRING_TYPE", "POST", "address_com");
$ins_company_com->addColumn("active_com", "NUMERIC_TYPE", "POST", "active_com");
$ins_company_com->setPrimaryKey("id_com", "NUMERIC_TYPE");

When using the addColumn method, there are several column types that can be used:

After all Transactions with their corresponding triggers were set and added to the Dispatcher, it can be executed:

// Execute all the registered transactions
$tNGs->executeTransactions();

The Dispatcher will execute each Transaction by calling the executeTransaction() method for each of them.

If any of the Transactions will export a recordset , we can ask the Dispatcher to search and retrieve it from its Transactions:

// Get the transaction recordset
$rscompany_com = $tNGs->getRecordset("company_com");
$row_rscompany_com = mysql_fetch_assoc($rscompany_com);
$totalRows_rscompany_com = mysql_num_rows($rscompany_com);