Question

CREATE TABLE credentials (
   credID SERIAL PRIMARY KEY,
   usrID INTEGER NOT NULL REFERENCES users(usrID),
   acctype CHAR(1) NOT NULL,

   CONSTRAINT acc_constraint
   CHECK (acctype = '4' OR acctype = '8' OR acctype = 'C' OR acctype = 'B'),
   cardnum VARCHAR(16),
   pinnum VARCHAR(8),
   credactive BOOLEAN NOT NULL DEFAULT true,
   created TIMESTAMP DEFAULT current_timestamp,
   CONSTRAINT cardset 
       CHECK ( ((acctype = 'C' OR acctype = 'B') AND 
        cardnum IS NOT NULL AND CHARACTER_LENGTH(cardnum) = 16) OR
       ((acctype = '4' OR acctype = '8') AND cardnum IS NULL) ),
   CONSTRAINT pinset
       CHECK ( (acctype = 'C' AND pinnum IS NULL) OR
               ((acctype = 'B' OR acctype = '4') AND
            pinnum IS NOT NULL AND CHARACTER_LENGTH(pinnum) = 4) OR
           (acctype = '8' AND pinnum IS NOT NULL AND 
    CHARACTER_LENGTH(pinnum) = 8) )
  );

错误1064（42000）：您的SQL语法有错误;检查与您的MySQL服务器版本相对应的手册，以便在＆＃39;附近使用正确的语法（ credID SERIAL PRIMARY KEY， usrID INTEGER NOT NULL REFERENCES使用＆＃39;在第1行

Answer 1

首先是列定义，然后是约束定义，不能在列的中间放置约束定义。如果你搬家：

CONSTRAINT acc_constraint
CHECK (acctype = '4' OR acctype = '8' OR acctype = 'C' OR acctype = 'B'),

到

之后

created TIMESTAMP DEFAULT current_timestamp,

然后你的桌子就可以了：

CREATE TABLE credentials (
    credID SERIAL PRIMARY KEY,
    usrID INTEGER NOT NULL REFERENCES users(usrID),
    acctype CHAR(1) NOT NULL,

    CONSTRAINT acc_constraint
    CHECK (acctype = '4' OR acctype = '8' OR acctype = 'C' OR acctype = 'B'),
    cardnum VARCHAR(16),
    pinnum VARCHAR(8),
    credactive BOOLEAN NOT NULL DEFAULT true,
    created TIMESTAMP DEFAULT current_timestamp,
    CONSTRAINT cardset 
        CHECK ( ((acctype = 'C' OR acctype = 'B') AND 
        cardnum IS NOT NULL AND CHARACTER_LENGTH(cardnum) = 16) OR
        ((acctype = '4' OR acctype = '8') AND cardnum IS NULL) ),
    CONSTRAINT pinset
        CHECK ( (acctype = 'C' AND pinnum IS NULL) OR
                ((acctype = 'B' OR acctype = '4') AND
            pinnum IS NOT NULL AND CHARACTER_LENGTH(pinnum) = 4) OR
            (acctype = '8' AND pinnum IS NOT NULL AND 
    CHARACTER_LENGTH(pinnum) = 8) )
    );

<强> Example on SQL Fiddle

然而，这是一项相对徒劳的练习，因为您可以在MySQL they are not enforced

中定义检查约束

检查约束的SQL错误：错误1064（42000）

1 个答案: