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both return a literal value. Notice the single quote mark that is used to designate the string value. Type each line of the code from Listing 2-1 into your query window. Listing 2-1. Statements Returning Literal Values SELECT 1 SELECT 'ABC' After typing the code in the query window, press F5 or click Execute to run the code. You will see the results displayed in two windows at the bottom of the screen, as shown in Figure 2-1. Because you just ran two statements, two sets of results are displayed.

In this chapter you installed Visual Basic 2005 Express, SQL Server 2005 Express, SQL Server Management Studio Express, SQL Server Books Online, and the sample Northwind database. You used sqlcmd to create and query the Northwind database. Now that we have our tools, let s get acquainted with them.

The whole purpose for connecting to a SQL Server instance with sqlcmd is to perform database chores namely, those that you can perform with T-SQL and sqlcmd statements. The sqlcmd utility is natively best for those chores that have short command statements and generate little or no output to the screen. An administrative statement, such as CREATE LOGIN, is ideal for the sqlcmd utility. Another example is any SELECT statement that generates an aggregate. The T-SQL statements in Figure 2-6 show how convenient it is to count the unique values in a column with the sqlcmd utility.

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then ExecuteScalar() would return the string Nancy instead of an integer, and you d get this exception:

The CREATE LOGIN statement adds a new login to a SQL Server Express instance. See 8 for extensive discussion and demonstrations on how to use this T-SQL statement.

Tip By highlighting one or more statements in the query window, you can run just a portion of the code. For

because you can t cast a String to an Integer. Another problem may occur if a query actually returns multiple rows where you thought it would return only one; for example, what if there were multiple employees with the last name Davolio In this case, ExecuteScalar() just returns the first row of the result and ignores the rest. If you use ExecuteScalar(), make sure you not only expect but actually get a single value returned.

You can work around the short input and output rule for the sqlcmd utility by using additional sqlcmd statement switches beyond those demonstrated already. When you need to run more than a couple of lines of statements, you can put the code into a file and then reference the file from a sqlcmd statement. There are two ways to accomplish this. First, you can use the i command-line switch following sqlcmd. The argument for the i switch is the path and file name containing the statements that you want to reference. There is no need to delimit the path and file with quotes (unless there are special characters, such as spaces, in a path name). Second, you can enter the :r sqlcmd keyword in response to a sqlcmd prompt, such as 1>. This keyword takes a string in double quotes to denote the path to a file. With either the i switch or the :r keyword, you can replace a set of statements with a single reference to a path and file. In fact, you can even debug the statements in Express SSMS and later run the statements in the file quickly and easily with the sqlcmd utility. The sqlcmd utility is ideally suited for rerunning a set of T-SQL statements whenever an IT professional or power user needs those statements run.

For queries where you re expecting multiple rows and columns to be returned, use the command s ExecuteReader method. ExecuteReader() returns a data reader, an instance of the SqlDataReader class that you ll study in the next chapter. Data readers have methods that allow you to read successive rows in result sets and retrieve individual column values. We ll leave the details of data readers for the next chapter, but for comparison s sake, we ll give a brief example here of using the ExecuteReader method to create a SqlDataReader from a command to display query results.

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