3

私は3つのテーブルを持っています:

CREATE TABLE "Names" (
"Name" TEXT(20) NOT NULL,
"Gender" TEXT(20) NOT NULL,
PRIMARY KEY ("Name", "Gender") 
);

CREATE TABLE "Snames" (
"Sname" TEXT(20) NOT NULL,
PRIMARY KEY ("Sname") 
);

CREATE TABLE "People" (
"ID" INTEGER NOT NULL,
"Name" TEXT(20) NOT NULL,
"Sname" TEXT(20) NOT NULL,
"Gender" TEXT(1) NOT NULL,
"FatherID" INTEGER,
"MotherID" INTEGER,
PRIMARY KEY ("ID") ,
CONSTRAINT "Father" FOREIGN KEY ("FatherID") REFERENCES "People" ("ID"),
CONSTRAINT "Mother" FOREIGN KEY ("MotherID") REFERENCES "People" ("ID"),
CONSTRAINT "Sname" FOREIGN KEY ("Sname") REFERENCES "Snames" ("Sname"),
CONSTRAINT "Name" FOREIGN KEY ("Name", "Gender") REFERENCES "Names" ("Name", "Gender")
);

私の問題は、独自のテーブルを参照する「FatherID」と「MotherID」の外部キー制約にあります。「FatherID」の性別列に「M」があり、「MotherID」の「F」である外部キーのみを許可することは可能ですか? 母/父が同じ行を参照できないようにすることは可能ですか?

基本的に: 父親は男性でなければなりません。母親は女性でなければなりません。あなたは自分の母親/父親になることはできません。

4

3 に答える 3

3

SQLite は、他の行から動的に取得された値を持つ式を含む制約をサポートしていないと思いますが、注目すべき外部キーの例外があります。

父親と母親の性別を確認するトリガーを作成する必要があります。

このテーブル定義を使用すると、次のようになります。

CREATE TABLE "People" (
    "ID" INTEGER NOT NULL,
    "Name" TEXT(20) NOT NULL,
    "Sname" TEXT(20) NOT NULL,
    "Gender" TEXT(1) NOT NULL,
    "FatherID" INTEGER,
    "MotherID" INTEGER,
    PRIMARY KEY ("ID") ,
    CONSTRAINT "Father" FOREIGN KEY ("FatherID") REFERENCES "People" ("ID"),
    CONSTRAINT "Mother" FOREIGN KEY ("MotherID") REFERENCES "People" ("ID"),
    CHECK (Gender IN ('M', 'F')),
    CHECK ("ID" NOT IN ("FatherID", "MotherID")));

これはINSERTトリガーである可能性があります（UPDATEトリガーを記述させてください）：

CREATE TRIGGER checkParentIdsOnInsert BEFORE INSERT ON People 
    WHEN new.FatherID IS NOT NULL OR new.MotherID IS NOT NULL
BEGIN
    SELECT CASE     
    WHEN ((SELECT Gender FROM People AS t1 WHERE t1.ID=new.FatherID) = 'F' 
            AND (SELECT Gender FROM People AS t2 WHERE t2.ID=new.MotherID) = 'M')
       THEN RAISE(ABORT, 'Father must be male and mother female') 
    WHEN ((SELECT Gender FROM People AS t3 WHERE t3.ID=new.FatherID) = 'F')
       THEN RAISE(ABORT, 'Father must be male') 
    WHEN ((SELECT Gender FROM People AS t4 WHERE t4.ID=new.MotherID) = 'M')
       THEN RAISE(ABORT, 'Mother must be female') 
    END; 
END;

いくつかの簡単なテスト:

sqlite> pragma foreign_keys=on;
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Jo", "Blo", "M", NULL, NULL);
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Za", "Bla", "F", NULL, NULL);
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Bad", "Kid", "M", 2, 1);
Error: Father must be male and mother female
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Bad", "Kid", "M", 2, NULL);
Error: Father must be male
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Bad", "Kid", "M", NULL, 1);
Error: Mother must be female
sqlite> INSERT INTO People (Name, SName, Gender, FatherID, MotherID) VALUES
   ...>     ("Good", "Kid", "M", 1, 2);
sqlite> .headers on
sqlite> .mode column
sqlite> SELECT * FROM People;
ID          Name        Sname       Gender      FatherID    MotherID  
----------  ----------  ----------  ----------  ----------  ----------
1           Jo          Blo         M                                 
2           Za          Bla         F                                 
3           Good        Kid         M           1           2
于 2012-09-02T16:44:51.820 に答える
2

以下は機能するはずですが、それ以外の場合は外部キー用に冗長な列がいくつか必要です( SQL Fiddle )

CREATE TABLE "People" (
"ID" INTEGER NOT NULL,
"Name" TEXT(20) NOT NULL,
"Sname" TEXT(20) NOT NULL,
"Gender" TEXT(1) NOT NULL,
"FatherID" INTEGER NULL,
"FatherGender" TEXT(1) NULL,
"MotherID" INTEGER NULL,
"MotherGender" TEXT(1) NULL,
PRIMARY KEY ("ID") ,
UNIQUE ("ID", "Gender"),
CHECK ("ID" NOT IN ("FatherID", "MotherID")),
CHECK ("FatherGender" = 'M'),
CHECK ("MotherGender" = 'F'),
CONSTRAINT "Father" FOREIGN KEY ("FatherID","FatherGender") REFERENCES "People" ("ID", "Gender"),
CONSTRAINT "Mother" FOREIGN KEY ("MotherID","MotherGender") REFERENCES "People" ("ID", "Gender")
);

INSERT INTO "People"
VALUES(1, 'Adam', '?', 'M', NULL, NULL, NULL, NULL);

INSERT INTO "People"
VALUES(2, 'Eve', '?', 'F', NULL, NULL, NULL, NULL);

INSERT INTO "People"
VALUES(3, 'Cain', '?', 'M', 1, 'M', 2, 'F');
于 2012-09-02T16:58:48.247 に答える
1

このようなタイプの制約を適用するには、作業を実行できるトリガーを使用する必要があります

編集: SQLite はトリガーをサポートします。ありがとう@catcall

于 2012-09-02T16:52:10.773 に答える