Question

每次我尝试制作外键或尝试执行ON DELETE CASCADE

我得到这样的错误：

Error starting at line 9 in command:
CONSTRAINT tp_landlordrole_FK FOREIGN KEY (zillowuseraccountid)
Error report:
Unknown Command

以下是我的代码

的示例

PROMPT 'Creating Table landlordrole'
CREATE TABLE tp_landlordrole
(
    landlordroleid          NUMBER(20) NOT NULL,
    zillowuseraccountid         NUMBER(20) NOT NULL,
    numberofpropertiesowned     Number(6),
CONSTRAINT tp_landlordrole_PK PRIMARY KEY ( landlordroleid ) ) ; 

CONSTRAINT tp_landlordrole_FK FOREIGN KEY (zillowuseraccountid)
    REFERENCES  tp_zillowuseraccount(zillowuseraccountid) ON DELETE CASCADE  ;

PROMPT Creating Index 'tp_landlordrole_I'
CREATE INDEX tp_landlordrole_I ON tp_landlordrole
( zillowuseraccountid );

PROMPT 'Creating Sequence tp_landlordroleid_seq for the tp_landlordrole table'
CREATE SEQUENCE tp_landlordroleid_seq START WITH 0 MINVALUE 0 NOCACHE;

欢迎任何建议!!

Answer 1

我相信你只需要一个alter table声明：

ALTER TABLE tp_landlordrole 
    ADD CONSTRAINT tp_landlordrole_FK
        FOREIGN KEY (zillowuseraccountid) REFERENCES  tp_zillowuseraccount(zillowuseraccountid) ON DELETE CASCADE  ;

但是，您可以直接在表定义中定义外键。

CREATE INDEX和CREATE SEQUENCE不需要ALTER TABLE。

Answer 2

根据OracleDocumentation定义约束的方法有多种：

一个。内联约束：

create table par(n number not null constraint par_pk primary key);
create table chld(m number constraint chld_pk primary key, 
                  n number not null constraint chld_fk references par(n) ON DELETE CASCADE);

drop table chld;
drop table par;

湾超出限制条件：

create table par(n number, constraint par_pk primary key(n));
create table chld(m number, n number not null, constraint chld_pk primary key(m), constraint chld_fk foreign key(n) references par(n) ON DELETE CASCADE);

drop table chld;
drop table par;

℃。单独ALTER TABLE声明。

create table par(n number);
alter table par add constraint par_pk primary key(n);
create table chld(m number, n number not null);
alter table chld add constraint chld_pk primary key(m);
alter table chld add constraint chld_fk foreign key(n) references par(n) ON DELETE CASCADE;

在您的情况下，您需要使用正确的语法来进行线外约束。

Answer 3

您需要先添加另一个ALTER TABLE命令，然后才能添加约束。这是完整的命令，假设您还需要定义父表tp_zillowuseraccount。

CREATE TABLE tp_zillowuseraccount(zillowuseraccountid NUMBER(20),
  PRIMARY KEY ( zillowuseraccountid ));

CREATE TABLE tp_landlordrole
(
    landlordroleid          NUMBER(20) NOT NULL,
    zillowuseraccountid         NUMBER(20) NOT NULL,
    numberofpropertiesowned     Number(6),
PRIMARY KEY ( landlordroleid ));

ALTER TABLE  tp_landlordrole 
ADD CONSTRAINT tp_landlordrole_FK FOREIGN KEY (zillowuseraccountid)
    REFERENCES  tp_zillowuseraccount(zillowuseraccountid) ON DELETE CASCADE;

CREATE INDEX tp_landlordrole_I ON tp_landlordrole
( zillowuseraccountid );
CREATE SEQUENCE tp_landlordroleid_seq START WITH 0 MINVALUE 0 NOCACHE;

Oracle：外键错误：未知命令

3 个答案: