Relational Databases for Each Table, Identify the Essay

Relational Databases

For each table, identify the primary key and the foreign key(s). If a table does not have a foreign key, write None in the space provided.

PRIMARY KEY

FOREIGN KEY

Truck

TRUCK_NUM

BASE_CODE, TYPE_CODE

Base

BASE_CODE

TYPE_CODE

Do the tables exhibit entity integrity? Answer yes or no, and then explain your answer.

ENTITY INTEGRITY

EXPLANATION

Truck

All rows under the primary key TRUCK_NUM are uniquely identified and there are no null entries

Base

All rows under the primary key BASE_CODE are uniquely identified and there are no null entries

All rows under the primary key TYPE_CODE are uniquely identified and there are no null entries

19. Do the tables exhibit referential integrity? Answer yes or no, and then explain your answer.Write NA (Not Applicable) if the table does not have a foreign key.

TABLE

REFERENTIAL INTEGRITY

EXPLANATION

Truck

Yes

All values under the foreign keys BASE_CODE and TYPE_CODE refer to a valid tuple in the BASE and TYPE tables, respectively. Null values are allowed

Base

NA

NA

Type….....