recursive delete trigger and ON DELETE CASCADE contraints are not deleting everything
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bitbonk
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Published on 2011-11-26T07:56:31Z
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2011/11/26
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I have a very simple datamodel that represents a tree structure:
The RootEntity
is the root of such a tree, it can contain children of type ContainerEntity
and of type AtomEntity
. The type ContainerEntity
again can contain children of type ContainerEntity
and of type AtomEntity
but can not contain children of type RootEntity
. Children are referenced in a well known order. The DB model for this is below.
My problem now is that when I delete a RootEntity
I want all children to be deleted recursively. I have create foreign key with CASCADE DELETE and two delete triggers for this. But it is not deleting everything, it always leaves some items in the ContainerEntity
, AtomEntity
, ContainerEntity_Children
and AtomEntity_Children
tables. Seemling beginning with the recursionlevel of 3.
CREATE TABLE RootEntity
(
Id UNIQUEIDENTIFIER NOT NULL,
Name VARCHAR(500) NOT NULL,
CONSTRAINT PK_RootEntity PRIMARY KEY NONCLUSTERED (Id),
);
CREATE TABLE ContainerEntity
(
Id UNIQUEIDENTIFIER NOT NULL,
Name VARCHAR(500) NOT NULL,
CONSTRAINT PK_ContainerEntity PRIMARY KEY NONCLUSTERED (Id),
);
CREATE TABLE AtomEntity
(
Id UNIQUEIDENTIFIER NOT NULL,
Name VARCHAR(500) NOT NULL,
CONSTRAINT PK_AtomEntity PRIMARY KEY NONCLUSTERED (Id),
);
CREATE TABLE RootEntity_Children
(
ParentId UNIQUEIDENTIFIER NOT NULL,
OrderIndex INT NOT NULL,
ChildContainerEntityId UNIQUEIDENTIFIER NULL,
ChildAtomEntityId UNIQUEIDENTIFIER NULL,
ChildIsContainerEntity BIT NOT NULL,
CONSTRAINT PK_RootEntity_Children
PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex),
-- foreign key to parent RootEntity
CONSTRAINT FK_RootEntiry_Children__RootEntity
FOREIGN KEY (ParentId) REFERENCES RootEntity (Id)
ON DELETE CASCADE,
-- foreign key to referenced (child) ContainerEntity
CONSTRAINT FK_RootEntiry_Children__ContainerEntity
FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id)
ON DELETE CASCADE,
-- foreign key to referenced (child) AtomEntity
CONSTRAINT FK_RootEntiry_Children__AtomEntity
FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id)
ON DELETE CASCADE,
);
CREATE TABLE ContainerEntity_Children
(
ParentId UNIQUEIDENTIFIER NOT NULL,
OrderIndex INT NOT NULL,
ChildContainerEntityId UNIQUEIDENTIFIER NULL,
ChildAtomEntityId UNIQUEIDENTIFIER NULL,
ChildIsContainerEntity BIT NOT NULL,
CONSTRAINT PK_ContainerEntity_Children
PRIMARY KEY NONCLUSTERED (ParentId, OrderIndex),
-- foreign key to parent ContainerEntity
CONSTRAINT FK_ContainerEntity_Children__RootEntity
FOREIGN KEY (ParentId) REFERENCES ContainerEntity (Id)
ON DELETE CASCADE,
-- foreign key to referenced (child) ContainerEntity
CONSTRAINT FK_ContainerEntity_Children__ContainerEntity
FOREIGN KEY (ChildContainerEntityId) REFERENCES ContainerEntity (Id)
ON DELETE CASCADE,
-- foreign key to referenced (child) AtomEntity
CONSTRAINT FK_ContainerEntity_Children__AtomEntity
FOREIGN KEY (ChildAtomEntityId) REFERENCES AtomEntity (Id)
ON DELETE CASCADE,
);
CREATE TRIGGER Delete_RootEntity_Children ON RootEntity_Children FOR DELETE
AS
DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted)
DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted)
GO
CREATE TRIGGER Delete_ContainerEntiy_Children ON ContainerEntity_Children FOR DELETE
AS
DELETE FROM ContainerEntity WHERE Id IN (SELECT ChildContainerEntityId FROM deleted)
DELETE FROM AtomEntity WHERE Id IN (SELECT ChildAtomEntityId FROM deleted)
GO
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