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

20. Identify the TRUCK table's candidate key(s).

22. Create the ERD for this database.

23. Create the relational diagram for this database.

Table name: TRUCK Primary key: TRUCK NUM Foreign key: BASE CODE, TYPE CODE TRUCK NUM BASE CODE TYPE CODE TRUCK MILES TRUCK BUY DATE TRUCK SERIAL NUM 1001 1002 1003 1004 1005 1006 1007 1008 1009 Database name: Ch03 TransCo 501 502 501 503 501 502 502 503 32123.5 76984.3 12346.6 2894.3 45673.1 193245.7 32012.3 44213.6 10932.9 23-Sep-07 AA-322-12212-W11 05-Feb-06 AC-342-22134-023 11-Noy-06 AC-445-78656-299 06-Jan-07 WQ-112-23144-T34 01-Mar-06 FR-998-32245-W12 15-Jul-03 AD-456-00845-R45 17-Oct-04 AA-341-96573-284 07-Aug-05 DR-559-22189-D33 12-Feb-08 DE-887-98456-E94 Table name: BASE Primary key: BASE_CODE Foreign key: none BASE CODE BASE CITY BASE STATE BASE AREA CODE BASE PHONE BASE MANAGER 501 Murfreesbo TN 502 Lexington 503 Cape Girardeau MO 504 Dalton 615 568 456 901 123-4567 234-5678 345-6789 456-7890 Andrea D. Gallager George H. Delarosa Maria J. Talindo Peter F. McAvee KY GA Table name: TYPE Primary key: TYPE CODE Foreign key: none TYPE CODE TYPE DESCRIPTION 1 Single box, double-axle 2 Single box, single-axle 3 Tandem trailer, single-axle