The repository \rstoetter\ctabledependencymanager-php
description
The class cTableDependencyManager is the main class of the repository \rstoetter\ctabledependencymanager-php., (*1)
The class cTableDependencyManager keeps the various dependencies to a certain target table. There can be lots of dependency paths to a certain table in the database. The dependency paths can consist of many tables, which establish the dependency between the source table and the target table. Self-referencing tables are considered, too., (*2)
Actually merely dependencies of a mysql database are supported, (*3)
The class \rstoetter\ctabledependencymanager\cTableDependencyManager keeps all dependencies of the database, which refer to a certain target table, (*4)
dependency paths
Such a dependency path could be the following one:, (*5)
TST_AUF_ITP_Stichwort_CLIENT_CLIENT -> TST_AUF_ITP_Stichwort_CLIENT -> TST_AUF_ITP_Stichwort -> TST_AUF_ITP_Stichwort -> ITP_Stichwort -> ITP_Zeitraum -> Klient -> Auswahl -> AuswahlTyp -> BUCHUNGSKREIS -> MANDANT, (*6)
- Here the source table TST_AUF_ITP_Stichwort_CLIENT_CLIENT depends on the table MANDANT ( the target table, the last one)
- all the tables mentioned before MANDANT refer to MANDANT in a certain way, too - in the given dependency order from right to left
- the dependency path shows, how the tables are connected in the database with FOREIGN KEYs
- The table TST_AUF_ITP_Stichwort is a self referencing table, therefore it is mentioned twice in the dependency path
How can I use it?
For example, if we want to do a cascading delete in the database and want to delete a record from the table MANDANT, then we have to
delete the dependencies in the database, which refer to the table MANDANT in any way., (*7)
First we have to delete affected records from TST_AUF_ITP_Stichwort_CLIENT_CLIENT, then from TST_AUF_ITP_Stichwort_CLIENT, then from
TST_AUF_ITP_Stichwort and so on, until we can delete the record in MANDANT without offending a constraint in the database., (*8)
The class cTableDependencyManager checks the whole database for the constraints between the tables and solves the order of the cascading delete., (*9)
It is a powerful weapon in order to ease the burden to keep track of all dependencies in your database., (*10)
BUT BE CAREFUL WHEN USING IT AS IT WOULD HELP TO DELETE ALL RECORDS FROM THE DATABASE WHICH DEPEND ON THE RECORD YOU WANT TO DELETE
IN THE TARGET TABLE, (*11)
helper classes
There are some helper classes, which are significantly involved in adding functionality to the class cTableDependencyManager:, (*12)
-
The class cTableDependency implements one dependency between two tables, (*13)
-
The class cTableDependency uses the class cTableDependencyPath, which implements the dependency between two tables and provides the table dependency path, (*14)
You will need PHP 7 or later to use this repository, (*15)
Usage:
$schema_name = 'give me the name of my database';
$table_name = 'give me the name of an existing table in the schema';
// open the database
$mysqli = new mysqli(
'the database host',
'the database account name',
'the password of the database account',
$schema_name
);
// retrieve the key column usage of the database
$obj_ac_key_column_usage = new \rstoetter\libsqlphp\cKEY_COLUMN_USAGE( $schema_name, $mysqli );
// build the sorted key column usage tree of the database
$obj_key_column_usage_tree = new \rstoetter\ckeycolumnusagetree\cKeyColumnUsageTree( $obj_ac_key_column_usage );
// create the table dependency manager for the table $table_name
$obj_table_dependency_manager = new \rstoetter\ctabledependencymanager\cTableDependencyManager( $table_name, $obj_key_column_usage_tree );
// print the table dependecies for the table $table_name managed by the table dependency manager
echo "\n in the database $schema_name refer the following tables to $table_name - directly and indirectly";
for ( $i = 0; $i < $obj_table_dependency_manager->GetTableDependencyCount( ); $i++ ) {
// retrieve object of type \rstoetter\ctabledependencymanager\cTableDependency
$obj_table_dependency = $obj_table_dependency_manager->GetTableDependency( $i );
echo "\n ";
// GetPathObject( ) returns type \rstoetter\ctabledependencymanager\cTableDependencyPath
echo $obj_table_dependency->GetPathObject( )->AsString( );
}
Installation
This project assumes you have composer installed. Simply add:, (*16)
"require" : {, (*17)
"rstoetter/ctabledependencymanager-php" : ">=1.0.0"
}, (*18)
to your composer.json, and then you can simply install with:, (*19)
composer install, (*20)
Namespace
Use the namespace \rstoetter\ctabledependencymanager in order to access the classes provided by the repository ctabledependencymanager-php, (*21)
See the project wiki of ctabledependencymanager-php for more technical informations., (*22)
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