Câu 2: 70-765: Provisioning SQL Databases

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 statement should you use?

1. A. CREATE TABLE Customer (SourceID int NOT NULL IDENTITY, CustomerID int NOT NULL IDENTITY, CustomerName varchar(255) NOT NULL);
2. B. CREATE TABLE Customer (SourceID int NOT NULL, CustomerID int NOT NULL PRIMARY KEY CLUSTERED, CustomerName varchar(255) NOT NULL);
3. C. CREATE TABLE Customer (SourceID int NOT NULL PRIMARY KEY CLUSTERED, CustomerID int NOT NULL UNIQUE, CustomerName varchar(255) NOT NULL);
4. D. CREATE TABLE Customer (SourceID int NOT NULL, CustomerID int NOT NULL, CustomerName varchar(255) NOT NULL, CONSTRAINT PK_Customer PRIMARY KEY CLUSTERED — đáp án hiện tại