Microsoft 9GD00001 manual Adding Tables, 185

Chapter 7: Working with Data 185

Adding Tables

The database itself will hold data for customers, orders, and order details that we introduced in the preceding chapter. The data will be held in tables that we’ll create in this section. In later sections, I’ll show you how to perform Create, Read, Update, and Delete (CRUD) operations on this data. Right now, you’ll learn how to create the tables.

To create a table, right-click the Tables branch under the database in Server Explorer and select Add New Table; you’ll see a Table Designer similar to Figure 7-3. Yours won’t have the CustomerID or Name columns yet; that’s coming up next.

The Table Designer allows you to add columns and configure the data type (such as integer, date, float, or character) and other details of each column and the table. Figure 7-3 shows a table with two columns, CustomerID of data type int and Name of data type nvarchar(50). Ensure that Null is unchecked for each column to avoid errors in code that doesn’t check for null later in this chapter.

NOTE

Databases, such as SQL Server, have their own type system, which doesn’t always match the .NET type system perfectly. That said, there are types that match very well; for instance, a SQL int is the same as a C# int or VB Integer. A SQL nvarchar(50) can be matched with a C# string or VB String. However, the nvarchar is limited to

50 characters, or whatever length is specified in parentheses, but the C# string and VB String don’t have a specified size. A full discussion of SQL types is out of scope, but you should be aware that there are differences between SQL and .NET types.

Figure 7-3 The Customer table