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Database design Ⅰ : Consider t

[问答题]

Database design : Consider the following conditions

i. The STUDENT may be taught by one and only one teacher . The TEACHER may be instructor of one or more STUDENT .

ii. The TEACHER may be responsible for one and only one CLASS . The CLASS may be the responsibility of one and only one TEACHER .

iii. The CLASS may be made of one of one or more STUDENT . The STUDENT must be a member of one and only one CLASS .

iv. The CLASS must have one and only are ROOM . The ROOM may belong to one or more CLASS .

Notes : Assume entity CLASS has the following attributes : CID and CNAME , entity ROOM has the following attributes : RID and LOCATION , entity STUDENT has the following attributes : SID , LASTNAME , and FIRSTNAME , entity TEACHER has following attributes : TID ,TEACHERNAME , and TITLE .

a) Construct an E-R diagram showing these relationships .

b) Construct appropriate relation schemas for the above E-R diagrams .

c) Create an index std_index on the student relation with SID as the search_key .

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