Câu 5: 1D0-541: CIW v5 Database Design Specialist

Consider the Information Engineering diagram shown in the exhibit for a building management company. Referential integrity must be maintained such that a building cannot be deleted when it has residents. Building_ID, R_ID, Room_Count and Room_Num are integer numbers, whereas Bldg_Name, Location andRes_Name are all represented by variable-length strings with a maximum of 20 characters. Which SQL statement best implements the relations shown in this diagram?

1. A. CREATE TABLE BUILDING ( Building_ID INTEGER NOT NULL PRIMARY KEY, Bldg_Name VARCHAR (20), Location VARCHAR (20), Room_Count INTEGER ); CREATE TABLE RESIDENT ( R_ID NOT NULL PRIMARY KEY, Room_Num INTEGER, Res_Name VARCHAR (20), Building_ID INTEGER NOT NULL, FOREIGN KEY Building_ID REFERENCES RESIDENT (Building_ID) ON DELETE NO CHECK);
2. B. CREATE TABLE BUILDING ( Building_ID INTEGER NOT NULL PRIMARY KEY, Bldg_Name VARCHAR (20), Location VARCHAR (20), Room_Count INTEGER ); CREATE TABLE RESIDENT ( R_ID NOT NULL PRIMARY KEY, Room_Num INTEGER, Res_Name VARCHAR (20), Building_ID INTEGER NOT NULL, FOREIGN KEY Building_ID REFERENCES BUILDING (Building_ID) ON DELETE NO CHECK ON UPDATE CASCADE);
3. C. CREATE TABLE BUILDING ( Building_ID INTEGER NOT NULL PRIMARY KEY, Bldg_Name VARCHAR (20), Location VARCHAR (20), Room_Count INTEGER ); CREATE TABLE RESIDENT ( R_ID NOT NULL PRIMARY KEY, Room_Num INTEGER, Res_Name VARCHAR (20), Building_ID INTEGER NOT NULL, FOREIGN KEY Building_ID REFERENCES BUILDING (Building_ID) ON DELETE NO CHECK ON UPDATE CASCADE); — đáp án hiện tại
4. D. CREATE TABLE BUILDING ( Building_ID INTEGER NOT NULL PRIMARY KEY, Bldg_Name VARCHAR (20), Location VARCHAR (20), Room_Count INTEGER ); CREATE TABLE RESIDENT ( R_ID NOT NULL PRIMARY KEY, Room_Num INTEGER, Res_Name VARCHAR (20), Building_ID INTEGER NOT NULL, FOREIGN KEY Building_ID REFERENCES BUILDING (Building_ID) ON DELETE NO CHECK ON UPDATE CASCADE);