不明白为什么我的 SQL 不起作用 [英] Don't understand why my SQL isn't working

问题描述

/* DROP TABLE STATEMENTS*/
DROP TABLE BUILDING CASCADE CONSTRAINTS PURGE;
DROP TABLE ROOM CASCADE CONSTRAINTS PURGE;
DROP TABLE CONFERENCESESSION CASCADE CONSTRAINTS PURGE;
DROP TABLE SPEAKER CASCADE CONSTRAINTS PURGE;

/* CREATE TABLE STATEMENTS*/
CREATE TABLE BUILDING(
BUILDINGNO CHAR(2),
BUILDINGWING VARCHAR2(15),
BUILDINGLANE VARCHAR2(15),
CONSTRAINT BUILDING_PK PRIMARY KEY(BUILDINGNO));

CREATE TABLE ROOM(
BUILDINGNO CHAR(2),
ROOMNO CHAR(2),
ROOMCAPACITY NUMBER(3),
CONSTRAINT ROOM_PK PRIMARY KEY(BUILDINGNO, ROOMNO),
CONSTRAINT ROOM_FK FOREIGN KEY(BUILDINGNO) REFERENCES BUILDING(BUILDINGNO));

CREATE TABLE SPEAKER(
SPEAKERID CHAR(2),
SPEAKERNAME VARCHAR2(20),
SPEAKERADDRESS VARCHAR2(50),
SPEAKERPHONE CHAR(12),
CONSTRAINT SPEAKER_PK PRIMARY KEY(SPEAKERID));

CREATE TABLE CONFERENCESESSION(
SESSIONID CHAR(4),
BUILDINGNO CHAR(2),
ROOMNO CHAR(2),
SPEAKERID CHAR(2),
SESSIONDATE DATE,
SESSIONPRICE NUMBER(4, 2),
CONSTRAINT CONFERENCE_PK PRIMARY KEY(SESSIONID),
CONSTRAINT CONFERENCE_FK1 FOREIGN KEY(BUILDINGNO)REFERENCES BUILDING(BUILDINGNO),
CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(ROOMNO) REFERENCES ROOM(ROOMNO),
CONSTRAINT CONFERENCE_FK3 FOREIGN KEY(SPEAKERID) REFERENCES SPEAKER(SPEAKERID));

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

运行上述代码时出现此错误:

I get this error when running the above code:

Table BUILDING 已删除.

Table BUILDING dropped.

Table ROOM 掉了.

Table ROOM dropped.

从第 4 行开始出错 -
删除表会议级联约束清除
错误报告 -
ORA-00942: 表或视图不存在
00942. 00000 - 表或视图不存在"
*原因:
*动作:

Error starting at line : 4 in command -
DROP TABLE CONFERENCESESSION CASCADE CONSTRAINTS PURGE
Error report -
ORA-00942: table or view does not exist
00942. 00000 - "table or view does not exist"
*Cause:
*Action:

Table SPEAKER 掉线了.

Table SPEAKER dropped.

表 BUILDING 已创建.

Table BUILDING created.

表室已创建.

表 SPEAKER 已创建.

Table SPEAKER created.

从第 28 行开始出错 -
创建表会议(
会话 ID 字符(4),
建筑无字符(2),
房间字符(2),
扬声器 ID 字符(2),
会议日期，
会话价格编号(4, 2),
CONSTRAINT CONFERENCE_PK PRIMARY KEY(SESSIONID),
CONSTRAINT CONFERENCE_FK1 FOREIGN KEY(BUILDINGNO)REFERENCES BUILDING(BUILDINGNO),
CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(ROOMNO) REFERENCES ROOM(ROOMNO),
CONSTRAINT CONFERENCE_FK3 FOREIGN KEY(SPEAKERID) REFERENCES SPEAKER(SPEAKERID))

Error starting at line : 28 in command -
CREATE TABLE CONFERENCESESSION(
SESSIONID CHAR(4),
BUILDINGNO CHAR(2),
ROOMNO CHAR(2),
SPEAKERID CHAR(2),
SESSIONDATE DATE,
SESSIONPRICE NUMBER(4, 2),
CONSTRAINT CONFERENCE_PK PRIMARY KEY(SESSIONID),
CONSTRAINT CONFERENCE_FK1 FOREIGN KEY(BUILDINGNO)REFERENCES BUILDING(BUILDINGNO),
CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(ROOMNO) REFERENCES ROOM(ROOMNO),
CONSTRAINT CONFERENCE_FK3 FOREIGN KEY(SPEAKERID) REFERENCES SPEAKER(SPEAKERID))

错误报告-
ORA-02270: 此列列表没有匹配的唯一键或主键
02270. 00000 - 此列列表没有匹配的唯一键或主键"
*原因:CREATE/ALTER TABLE 语句中的 REFERENCES 子句提供的列列表在被引用表中没有匹配的唯一键或主键约束.
*操作:使用 ALL_CONS_COLUMNS 目录视图查找正确的列名

Error report -
ORA-02270: no matching unique or primary key for this column-list
02270. 00000 - "no matching unique or primary key for this column-list"
*Cause: A REFERENCES clause in a CREATE/ALTER TABLE statement gives a column-list for which there is no matching unique or primary key constraint in the referenced table.
*Action: Find the correct column names using the ALL_CONS_COLUMNS catalog view

有什么帮助吗?

推荐答案

CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(ROOMNO) REFERENCES ROOM(ROOMNO):外键必须引用整个em> 另一个表的主键(或唯一键).所以只需添加 buildingno:

CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(ROOMNO) REFERENCES ROOM(ROOMNO): A foreign key has to reference the entire primary key (or unique key) of another table. So simply add buildingno:

CONSTRAINT CONFERENCE_FK2 FOREIGN KEY(BUILDINGNO, ROOMNO) REFERENCES ROOM(BUILDINGNO, ROOMNO)

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