references.md

Referential Integrity

One-To-Many

PLANT generates the entities so that you don't have to do anything else; whenever you show an entity in an index, edit or add view, the assignable entities are shown within a selection box for the assignment. beetRoot handles everything with one-to-many references - no code is required. The only important note here is to follow the naming conventions of beetRoot:

• The table that refers to products has the integer field product_id.

Further examples:

• Table properties -> reference table with integer field property_id.
• Table tasks -> reference table with integer field task_id.

Many-To-Many

You have the option of using the built-in association mechanism to create many-to-many relationships. However, some code is required for this to work. To do this, overwrite the extractCustomSingleInputDiv method of the edit and add handlers to handle the corresponding column that refers to a relation table. The following examples show how this is done (many-to-many user-role relationship):

• ExtUsersAddHandler
• ExtUsersEditHandler

The methods already contain the correct IDs to handle the relationships. When you create a relationship table in the database, it only needs the reference key, no ID is needed for this table, of course you can add more columns if they are needed for some other reason. E.g. user-role table:

CREATE TABLE users_roles (
    "user_id" INT UNSIGNED NOT NULL,
    "role_id" INT UNSIGNED NOT NULL,
    "created" TIMESTAMP(3) DEFAULT NOW(),
    PRIMARY KEY ("user_id", "role_id"),
    FOREIGN KEY ("user_id") REFERENCES users("id") ON DELETE CASCADE,
    FOREIGN KEY ("role_id") REFERENCES roles("id") ON DELETE CASCADE
);
ALTER TABLE users_roles ADD INDEX "idx_user_id" ("user_id");
ALTER TABLE users_roles ADD INDEX "idx_role_id" ("role_id");

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