Mysql create table with multiple foreign key on delete set null

Question

I am trying to create a database with multiple foreign keys with delete/ update constraints, but I got a error code 1005 with following sql scripts:

CREATE T         


        

Answer 1

Your foreign key rule is ON DELETE SET NULL but your column definition is NOT NULL.

Either change your column definition and remove the NOT NULL part or overthink your foreign key rule. That works:

CREATE TABLE Vineyard (
    VineyardID smallint auto_increment,
    VineyardName VARCHAR(45) NOT NULL,
    FarmerID    smallint,
    GrapeID smallint,
    ComeFrom    varchar(45) NOT NULL,
    HarvestedAmount int,
    RipenessPercent int,
    PRIMARY KEY (VineyardID),
    FOREIGN KEY (FarmerID) REFERENCES Worker(WorkerID)
        ON DELETE SET NULL
        ON UPDATE CASCADE,
    FOREIGN KEY (GrapeID) REFERENCES Grape(GrapeID)
        ON DELETE SET NULL
        ON UPDATE CASCADE
)Engine=InnoDB;

SQLFiddle demo