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70-463 · Question #135

70-463 Question #135: Real Exam Question with Answer & Explanation

The correct answer is D: CREATE TABLE Customer. The correct CREATE TABLE statement must define a composite primary key on (SourceID, CustomerID) in that column order. This achieves both requirements simultaneously: (1) A composite PRIMARY KEY constraint enforces uniqueness of the CustomerID+SourceID combination, preventing dup

Question

You are a database developer of a Microsoft SQL Server 2012 database. You are designing a table that will store Customer data from different sources. The table will include a column that contains the CustomerID from the source system and a column that contains the SourceID. A sample of this data is as shown in the following table. You need to ensure that the table has no duplicate CustomerID within a SourceID . You also need to ensure that the data in the table is in the order of SourceID and then CustomerID. Which Transact-SQL stat.ement should you use?

Options

  • ACREATE TABLE Customer
  • BCREATE TABLE Customer
  • CCREATE TABLE Customer
  • DCREATE TABLE Customer

Explanation

The correct CREATE TABLE statement must define a composite primary key on (SourceID, CustomerID) in that column order. This achieves both requirements simultaneously: (1) A composite PRIMARY KEY constraint enforces uniqueness of the CustomerID+SourceID combination, preventing duplicate CustomerIDs within any given SourceID. (2) Because a PRIMARY KEY creates a clustered index by default, and the key is defined as (SourceID, CustomerID), the physical data is stored and ordered by SourceID first, then CustomerID - exactly as required. The other options either use incorrect key column order, define only a single-column key, or use a non-clustered index that would not enforce the required physical storage order.

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