ER DIAGRAM OF CARGO SHIP MANAGEMENT.

A crew of people will be controlled by a captain.A vessel can have crew of people but  that crew of people can be present only in one  vessel.In a vessel,the captain has the right to give commands.Vessel can be a SOTL.Many regions are patrolled by vessels and many vessels patrols many regions to make sure that there is no trouble there.

▪ Crew is uniquely identified by name.It also consist of age,rank.

▪Captain is uniquely identified by name.

▪Vessel is uniquely identified by ship name.It also consists of flank speed,  displacement.

▪Region is uniquely identified by region name.

▪SOTL is uniquely identified by class name.It consist of size primary,num_primary.

Draw an ER diagram for the ship cargo database with the various attributes and relationships.

ANSWER:

1.Identify the entities.

→CREW

→CAPTAIN

→REGION

→SOTL

→VESSEL

2.Identify the relationships.

› A CREW IS CONTROLLED BY A CAPTAIN.

CARDINALITY-1:1

›MANY CREWS ARE ASSIGNED TO ONE VESSEL.

CARDINALITY-N:1

›CAPTION GIVE COMMANDS IN A VESSEL.

CARDINALITY-1:1

›MANY REGIONS ARE PAROLLED BY MANY VESSELS.

CARDINALITY-N:N

›VESSEL IS A SOTL.

CARDINALITY-N:N

erd relatn 1

3.Identify key attributes for each entities

> CREW-CREW_NAME

>CAPTAIN-CAP_NAME

>REGION-REGION_NAME

>SOTL-CLASS_NAME

>VESSEL-SHIP_NAME

4.Identify other relevant attributes.

▪CREW

>CREW_NAME

>AGE

>RANK

▪CAPTAIN

>CAPTN_NAME

▪REGION

>REGION_NAME

▪VESSEL

>SHIP_NAME

>FLANK_SPEED

>DISPLACMENT

▪SOTL

>CLASS_NAME

>SIZE_PRIMARY

>NUM_PRIMARY

5.Complete ER diagram.

erd dia2

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