- Making Virtual Spies—Creating Spy Net in SQL Server 2000
- Creating the SQL Spy Net Application Database
- Using the Data Definition Language (DDL) to Create Databases and Objects
- Bringing Our Data Model and Database Together
- Summary
- Next Steps
Creating the SQL Spy Net Application Database
As in most tasks within SQL Server 2000, there are many different ways to achieve the same thing. You can use a nice user interface or you can enter Transact-SQL directly against the database.
Even most of the configuration options for the model database that we just went through can be set using Transact-SQL!
What methods are available to create a database in SQL Server 2000? Listed here are the three basic methods you can use to create a database:
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Run the Database Creation Wizard, which is contained in Enterprise Manager. This is a simple wizard that allows you to enter the parameters that you require to model your database on. Although using the wizard is an effective and simple way to create an application database, as a DBA you usually will use one of the two following methods because they are a little quicker. For this reason we will not cover the creation of a database through the wizard.
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Using the UI in Enterprise Manager to create a database. This is done by selecting the New Database option from the pop-up menu when you right-click the database folder within Enterprise Manager. This is the most common way of creating a database in SQL Server 2000, probably because of the friendly user interface you are provided. We will initially create our application database with this method.
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Enter the CREATE DATABASE Transact-SQL statement directly into Query Analyzer. This is by far the most difficult to remember (I always have trouble remembering the exact syntax), but it gives you the most flexibility and is probably the preferred way for most DBAs. The reason? The knowledge is cross-transferable. Even if you move to another database management system (heaven forbid), you will know the basic structure of the statement.
As you can see, the ability to create a database quickly and easily (by all levels of users) is well catered for in SQL Server 2000.
Using Enterprise Manager to Create Our Application Database
In this section we will develop the database through the user interface in Enterprise Manager. Unfortunately though, I am going to make an assumption about the PC on which you are running SQL Server 2000.
I am assuming that you do not have multiple hard drives. On the PC that I am using I have three separate hard drives, but not everybody will have the same configuration, so we will go with the lowest common denominator. However, if you do have the ability to specify different drives for the data and transaction logs, feel free to do so (this was discussed in the section "Configuring the Model Database to Meet Our SQL Spy Net Application Requirements," earlier in this chapter).
Well, let's get down to business!
If you do not have Enterprise Manager running, start the application now. Drill through the tree-view control and locate the Databases folder. If you right-click the Databases folder you will be presented with a pop-up menu similar to that shown in Figure 3.11. Select the New Database option.
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Figure
3.11
The create a new database command in Enterprise Manager.
The next screen collects some basic information in regard to the creation of a database. We are going to call our database SQLSpyNet. This is the name that SQL Server 2000 will use to recognize our application database. You could name your database something else, but throughout the rest of the book I will refer to the SQLSpyNet naming convention, so it will be easier if you use this name. The new screen will look similar to that shown in Figure 3.12.
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Figure
3.12
The Create New Database Properties dialog screen.
The General Tab
The General tab is relatively limited in the actions that you can perform. Other than entering the database name the only other action is the collation name. This is used to set the type of locale configuration that the database will have. You only need to alter this if your database will talk to a computer that has a different locale setting than your server (your PC) has.
The locale refers to the way the characters on your computer are displayed and stored. The locale is set for your machine when the operating system is installed. Different countries and languages use different locale settings so that unique characters to their language can be displayed. For example, the U.S. English character set uses the Latin1_General locale.
Because we are developing our application from scratch and currently do not have a requirement to communicate with other databases, we shall leave the database default to the server's settings.
Notice that the screen has two other tabs: the tabs for configuring the data files and the transaction logs. If you have a quick look, you will see they imitate the settings (except the filenames) that we adjusted in the section, "Configuring the Model Database to Meet Our SQL Spy Net Application Requirements."
Click OK now, and SQL Server 2000 will create your first database for you! Simple, isn't it?
Note - If you don't see your new database in the Databases folder, right-click and select Refresh.
The Properties Tab
Now select the SQLSpyNet database, right-click, and choose the Properties option. You will be presented with a screen similar to the one that we saw in Figure 3.9. Click the Options tab and you will see the screen shown in Figure 3.13.
We are going to check that the options that we set in the model database are reflected in our new database. If the settings are correct they should mirror the settings in Figure 3.13. When you are happy with the settings, click OK.
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If you explore in the new database (namely the Tables, Views, and Stored Procedures folders), you will see that some database objects have already been created. These are the system objects that SQL Server 2000 uses to keep track of the objects contained in our database. For example, if you open the Tables folder you will see a list of system tables.
Figure
3.13
SQLSpyNet Database Properties screen—Options tab.
Note - If you do not see the system tables, you will need to alter the registration properties of Enterprise Manager. You can do this by selecting the ServerName\InstanceName icon, right-clicking, and then selecting Edit SQL Server Registration Properties; you will see the registration dialog window.
When the dialog window starts, ensure the Show System Databases and System Objects box is selected. Click OK.
For more information, see the section "Configuring SQL Server 2000" in Appendix B or "Setting the sa Password," earlier in this chapter.
These system tables contain information about the schema of the database, for example the names of tables, views, and stored procedures (in the sysobjects table), the names, size, type of columns within tables (the syscolumns table), and the names and access of the users (the sysusers table). This allows SQL Server 2000 to track not only the tables, views, and stored procedures, but also the users and many other objects defined in our database.
Well, that is about all we have to do with our database so far. We can now delete (drop) the database. "What?!?" I hear you cry.
We know how to develop a database through the nice UI that Enterprise Manager provides, so let's learn how to do this through Transact-SQL code.
Note - For the rest of the application development we are going to use a mixture of Transact-SQL code (my preference) and the UI in Enterprise Manager. However, we will not repeat tasks as we have done in this section. Instead, we will implement our changes and move to the next task, or else we will never get our application up and running!
Dropping Spies Like Flies
First, though, we need to drop the SQLSpyNet database that we just created.
Start Query Analyzer through the start menu group or by selecting Tools from the menu bar in Enterprise Manager and selecting the SQL Server Query Analyzer option. Then enter the code in Listing 3.1 into the Transact-SQL window, as shown in Figure 3.14.
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Figure
3.14
Removing our database by using code in the Query Analyzer window.
Listing 3.1—Deleting Our SQLSpyNet Database Using Transact-SQL Code
1: USE master 2: GO 3: IF EXISTS (SELECT name FROM master.dbo.sysdatabases 3a:WHERE name = 'SQLSpyNet') 4: DROP DATABASE [SQLSpyNet] 5: GO
After you have entered the code in the window, click the Green Triangle in the toolbar, or use the hotkeys Alt+X to run the code.
After the code has finished running you will see two statements of confirmation that the task has completed. They will be similar to these:
1: Deleting database file'c:\mssql2000\MSSQL$MYSQLSERVER\data\SQLSpyNet_Log.LDF'. 2: Deleting database file
Tip - Save these file paths because you will need them later when we re-create the database.
This confirms that the data file and the transaction log have been deleted.
Note - If you did not name your database SQLSpyNet, enter the name you chose in place of SQLSpyNet.
The meaning of the code is relatively simple. The first two lines of code (1 and 2) ensure that this statement is being fired from the master database. All database manipulation such as DROP and CREATE should be fired from the master database.
The third two lines (3 and 3a) check the existence of your database within our instance of SQL Server 2000; this is called a control-of-flow statement, and there will be more on this in Chapter 4.
The fourth line of code actually performs the database drop, and the fifth line executes the two former statements consecutively.
Do not worry about the SELECT statement or the WHERE criteria; I explain this in more detail in Chapter 4.
If you now refresh your Databases folder in either Enterprise Manger or Query Analyzer (through the Object Browser; refer to Chapter 2), you will see that the SQLSpyNet database has gone!
There we go; so far we have created and deleted a database by using two of the tools available in SQL Server 2000. We will now re-create the SQLSpyNet database through Transact-SQL code; so don't close down Query Analyzer yet!