mysql - 无法添加外键约束

Question

CREATE TABLE tblTransaction (
   strTransCode VARCHAR(50) NOT NULL,
   dtmTransDate datetime,
   strTransDesc VARCHAR(50) NOT NULL,
   dblTransAmt double,
   intVoucRefCodeTrans INT,
   FOREIGN KEY (intVoucRefCodeTrans) REFERENCES tblVoucher (intVoucRefCode) ON DELETE RESTRICT ON UPDATE CASCADE,
   PRIMARY KEY (strTransCode)
   )ENGINE=InnoDB;
CREATE TABLE tblVoucher (
   intVoucRefCode INT,
   strVoucRefDesc VARCHAR(50) NOT NULL,
   dtmVoucDate datetime,
   PRIMARY KEY (intVoucRefCode)
   )ENGINE=InnoDB;

这些是我的表，我不知道为什么它显示“无法添加外键约束”，请帮忙

Answer 1

首先创建tblVoucher表，然后在tblTransaction表中引用它

CREATE TABLE tblVoucher (
   intVoucRefCode INT,
   strVoucRefDesc VARCHAR(50) NOT NULL,
   dtmVoucDate datetime,
   PRIMARY KEY (intVoucRefCode)
   )ENGINE=InnoDB;

CREATE TABLE tblTransaction (
   strTransCode VARCHAR(50) NOT NULL,
   dtmTransDate datetime,
   strTransDesc VARCHAR(50) NOT NULL,
   dblTransAmt double,
   intVoucRefCodeTrans INT,
   FOREIGN KEY (intVoucRefCodeTrans) REFERENCES tblVoucher (intVoucRefCode) ON DELETE RESTRICT ON UPDATE CASCADE,
   PRIMARY KEY (strTransCode)
   )ENGINE=InnoDB;

DEMO