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Doctrine class table inheritance help


NotionCommotion

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Trying to create a model where Parent1 and Parent2 extend Grandparent, and Child1_1 and Child1_2 extend Parent1 as well as Child2_1 and Child2_2 extend Parent2.

I set up my definitions:

Grandparent:
    type: entity
    table: grandparent_table
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_grandparent
        type: string
    repositoryClass: GrandParent
    id:
        id:
            type: integer
            generator:
                strategy: AUTO
    fields:
        GrandParent_Item1:
            type: string
        GrandParent_Item2:
            type: string
Parent1:
    type: entity
    table: parent_table1
    extends: Grandparent
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_parent1
        type: string
    id:
        id:
            associationKey: true
    fields:
        Parent1_Item1:
            type: string
        Parent1_Item2:
            type: string
Parent2:
    type: entity
    table: parent_table2
    extends: Grandparent
    inheritanceType: JOINED
    discriminatorColumn:
        name: discriminator_column_parent2
        type: string
    id:
        id:
            associationKey: true
    fields:
        Parent2_Item1:
            type: string
        Parent2_Item2:
            type: string
Child1_1:
    extends: Parent1
    type: entity
    table: child1_1_table
    id:
        id:
            associationKey: true
    fields:
        Child1_1_Item1:
            type: string
        Child1_1_Item2:
            type: string
Child1_2:
    extends: Parent1
    type: entity
    table: child1_2_table
    id:
        id:
            associationKey: true
    fields:
        Child1_2_Item1:
            type: string
        Child1_2_Item2:
            type: string
Child2_1:
    extends: Parent2
    type: entity
    table: child2_1_table
    id:
        id:
            associationKey: true
    fields:
        Child2_1_Item1:
            type: string
        Child2_1_Item2:
            type: string
Child2_2:
    extends: Parent2
    type: entity
    table: child2_2_table
    id:
        id:
            associationKey: true
    fields:
        Child2_2_Item1:
            type: string
        Child2_2_Item2:
            type: string

 And then generate my entities:       

$ vendor/bin/doctrine orm:generate-entities -vvv src

 Processing entity "Child1_1"
 Processing entity "Child1_2"
 Processing entity "Child2_1"
 Processing entity "Child2_2"
 Processing entity "Grandparent"
 Processing entity "Parent1"
 Processing entity "Parent2"


 [OK] Entity classes generated to "/var/www/doctrine/src"

Note that I needed to manually edit the Parent1 and 2 classes to extend Grandparent as well as the individual Child classes to extend their applicable Parent.

Next, I create the schema:

$ vendor/bin/doctrine orm:schema-tool:create --dump-sql

 The following SQL statements will be executed:

     CREATE TABLE child1_1_table (id INT NOT NULL, Child1_1_Item1 VARCHAR(255) NOT NULL, Child1_1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child1_2_table (id INT NOT NULL, Child1_2_Item1 VARCHAR(255) NOT NULL, Child1_2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child2_1_table (id INT NOT NULL, Child2_1_Item1 VARCHAR(255) NOT NULL, Child2_1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE child2_2_table (id INT NOT NULL, Child2_2_Item1 VARCHAR(255) NOT NULL, Child2_2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE grandparent_table (id INT AUTO_INCREMENT NOT NULL, GrandParent_Item1 VARCHAR(255) NOT NULL, GrandParent_Item2 VARCHAR(255) NOT NULL, discriminator_column_grandparent VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE parent_table1 (id INT NOT NULL, Parent1_Item1 VARCHAR(255) NOT NULL, Parent1_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     CREATE TABLE parent_table2 (id INT NOT NULL, Parent2_Item1 VARCHAR(255) NOT NULL, Parent2_Item2 VARCHAR(255) NOT NULL, PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ENGINE = InnoDB;
     ALTER TABLE child1_1_table ADD CONSTRAINT FK_3445750EBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child1_2_table ADD CONSTRAINT FK_5AD6F93BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child2_1_table ADD CONSTRAINT FK_DC849CBBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE child2_2_table ADD CONSTRAINT FK_3C205356BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE parent_table1 ADD CONSTRAINT FK_5386E15BBF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;
     ALTER TABLE parent_table2 ADD CONSTRAINT FK_CA8FB0E1BF396750 FOREIGN KEY (id) REFERENCES grandparent_table (id) ON DELETE CASCADE;

I see how Grandparent has discriminatorColumn discriminator_column_grandparent as expected.

But why doesn't Parent1 and Parent2 have discriminatorColumn's discriminator_column_parent1 and discriminator_column_parent2?

Note that I've also tried making Grandparent, Parent1, and Parent2 abstract but get the same results.  I've also messed around with Mapped Superclasses, but I don't think they are applicable for my use (correct me if you think I am wrong).

Thanks!

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6 hours ago, NotionCommotion said:

Ah, it just stores the name of the final class in the discriminator column, and this column is not a "field" that one would explicitly set.

Right. Each child comes from the parent and each parent comes from the grandparent, and the grandparent table already has a discriminator. That one column can handle all descendants of the grandparent, not just its immediate children.

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