Question

create table project_supervisor (
   supervisor_ID VARCHAR2 (5) Primary key,
   last_name varchar2 (250),
   other_names varchar2 (250)
);

 CREATE TABLE Project_description 
 (
    project_id VARCHAR2 NOT NULL,
    project_title varchar,
    project_summary varchar,
    PRIMARY KEY (project_id),
      FOREIGN KEY (supervisor_ID)
    REFERENCES  "project_supervisor" (supervisor_ID)
);

Answer 1

create table project_supervisor (
   supervisor_ID VARCHAR2 (5) Primary key,
   last_name varchar2 (250),
   other_names varchar2 (250)
);

 CREATE TABLE Project_description 
 (
    project_id VARCHAR2(100) NOT NULL,
    project_title varchar(100),
    project_summary varchar(100),
    supervisor_ID varchar(5),
    PRIMARY KEY (project_id),
    FOREIGN KEY (supervisor_ID) REFERENCES  project_supervisor (supervisor_ID)
);

Answer 2

像这样创建它们：

CREATE TABLE project_supervisor ( 
             supervisor_ID VARCHAR2 (5) Primary key, 
             last_name varchar2 (250), 
             other_names varchar2 (250) 
            );

CREATE TABLE Project_description ( 
             project_id VARCHAR2(5) NOT NULL,
             supervisor_ID varchar(5), 
             project_title varchar(25), 
             project_summary varchar(25),
             CONSTRAINT pk_project_id PRIMARY KEY(project_id), 
             CONSTRAINT fk_supervisor_ID FOREIGN KEY(supervisor_ID) 
                        REFERENCES project_supervisor (supervisor_ID) 
            );

您需要包含varchar列的长度。
constraint定义必须格式正确。
supervisor_ID列。
project_supervisor不应该被引用。

Demo

Answer 3

您需要在第二个表格中添加supervisor_ID：

CREATE TABLE project_supervisor 
  ( 
     supervisor_id VARCHAR2 (5) PRIMARY KEY, 
     last_name     VARCHAR2 (250), 
     other_names   VARCHAR2 (250) 
  ); 

CREATE TABLE project_description 
  ( 
     project_id      VARCHAR2 NOT NULL, 
     project_title   VARCHAR, 
     project_summary VARCHAR, 
     supervisor_id   VARCHAR2(5), 
     PRIMARY KEY (project_id), 
     FOREIGN KEY (supervisor_id) REFERENCES project_supervisor (supervisor_id) 
  );

此外，围绕表名不需要"。

为什么我一直收到这个错误＆＃34;错误报告 - ORA-00906：缺少左括号00906. 00000 - ＆＃34;

3 个答案: