Introduction to Database Creation

A database is primarily a group of computer files that each has a name and a location. Just as there are different ways to connect to a server, in the same way, there are different ways to create a database.

To create a new database in Microsoft SQL Server Management Studio, in the Object Explorer, you can right-click the Databases node and click New Database... This would open the New Database dialog box.

• A name can start with either a letter (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, or Z), a digit (0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), an underscore (_) or a non-readable character. Examples are _n, act, %783, Second
• After the first character (letter, digit, underscore, or symbol), the name can have combinations of underscores, letters, digits, or symbols. Examples are _n24 or act_52_t
• A name can include spaces. Example are c0untries st@ts, govmnt (records), or gl0b# $urvey||

Because of the flexibility of SQL, it can be difficult to maintain names in a database. Based on this, there are conventions we will use for our objects. In fact, we will adopt the rules used in C/C++, C#, Pascal, Java, and Visual Basic, etc. In our databases:

• Unless stated otherwise (we will mention the exceptions, for example with variables, tables, etc), a name will start with either a letter (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, or Z) or an underscore
• After the first character, we will use any combination of letters, digits, or underscores
• A name will not start with two underscores
• If the name is a combination of words, at least the second word will start in uppercase. Examples are Countries Statistics, Global Survey, _RealSport, FullName, or DriversLicenseNumber

After creating an object whose name includes space, whenever you use that object, include its name between [ and ]. Examples are [Countries Statistics], [Global Survey], or [Date of Birth]. Even if you had created an object with a name that doesn't include space, when using that name, you can still include it in square brackets. Examples are [UnitedStations], [FullName], [DriversLicenseNumber], and [Country].

1. In the Object Explorer, right-click Databases and click New Database...
    
   
2. In the Name text box, type MotorVehicleAdministration

Whenever a new database is created, the server wants to keep track of who created that database. This is known as the database owner. By default, Microsoft SQL Server creates a special account named dbo (for database owner). When you create a database but do not specify the owner, this account is used. The dbo account is also given rights to all types of operations that can be performed on the database. This is convenient in most cases. Still, if you want, you can specify another user as the owner of the database. Of course, the account must exist, which means you should have previously created it or you can use an existing one.

To visually specify the owner of a database you are creating, you can click <default> in the Owner text box, type the name of the domain, followed by the back slash, and followed by the user name who will own the database. Alternatively, you can click the ellipsis button on the right side of the Owner text box. This would open the Select Database Owner dialog box:

In the Enter the Object Names to Select dialog box, enter the full name or the username of the user to whom you want to assign the database. After doing that, click Check Names. If the name is right, the dialog box would accept it. If the name is not right, you would receive an error. You can click the Browse button. This would open the Browse For Objects dialog box. If you see the user object you want to use, click its check box and click OK.

• In the Owner dialog box, click <default> and type DomainName\pkatts (replace DomainName with the name of your domain; otherwise, skip this step) (you can also click the browser button on the right side of Owner to locate and select the desired username)

1. Scroll to the right side and, under the Path header, notice the location of the file
2. Start Windows Explorer
3. In the left frame, click the C: drive
4. Right-click a blank area in the right frame -> New -> Folder
5. Type Microsoft SQL Server Database Development as the name of the new folder
6. Return to the New Database dialog box.
   Under Path, click the browse button
7. Locate the Microsoft SQL Server Database Development folder you created and select it
8. Do the same for the other path
9. Click OK

To specify more options with code, Microsoft SQL Server ships with various sample codes you can use for different assignments. For example, you can use sample code to create a database. The sample codes that Microsoft SQL Server are accessible from the Template Explorer.

To access the Template Explorer, on the main menu, you can click View -> Template Explorer. Before creating a database, open a new query window. Then:

• To create a new database using sample code, in the Template Explorer, expand the Databases node, then drag the Create Database node and drop it in the query window. The new database would be created in the server that holds the current connection
• If you have access to more than one server, to create a database in another server or using a different connection, in the Template Explorer, expand the Databases node, right-click Create Database and click Open. In the Connect to Database Engine dialog box, select the appropriate options, and can click OK

With any of these actions, Microsoft SQL Server would generate sample code for you:

-- =============================================
-- Create database template
-- =============================================
USE master
GO

-- Drop the database if it already exists
IF  EXISTS (
	SELECT name 
		FROM sys.databases 
		WHERE name = N'<Database_Name, sysname, Database_Name>'
)
DROP DATABASE <Database_Name, sysname, Database_Name>
GO

CREATE DATABASE <Database_Name, sysname, Database_Name>
GO

You would then need to edit the code and execute it to create the database. From the previous lessons and sections, we have reviewed some characters uch as the comments -- and some words or expressions such as GO, CREATE DATABASE, and SELECT. We will study the other words or expressions in future lessons and sections.

If you have created a database but don't need it anymore, you can delete it. It is important to know, regardless of how you create a database, whether using SQL Server Management Studio, code in the query window, or the Command Prompt, every database can be accessed by any of these tools and you can delete any of the databases using any of these tools.

As done with creating a database, every tool provides its own means.

To delete a database in SQL Server Management Studio, in the Object Explorer, expand the Databases node, right-click the undesired database, and click Delete. A dialog box would prompt you to confirm your intention. If you still want to delete the database, you can click OK. If you change your mind, you can click Cancel.

1. In the Object Explorer, right-click MotorVehicleAdministration and click Delete
    
   
   
2. In the Delete Object dialog box, click OK

To delete a database in SQL Query Analyzer, you use the DROP DATABASE expression followed by the name of the database. The formula used is:

DROP DATABASE DatabaseName;

Before deleting a database in SQL, you must make sure the database is not being used or accessed by some one else or by another object.

1. On the Standard toolbar, click the New Query button
2. To delete a database, type:
    

   DROP DATABASE RealEstate1; GO

3. Press F5 to execute the statement

While writing code in a Query Window, you should always know what database you are working on, otherwise you may add code to the wrong database. To programmatically specify the current database, type the USE keyword followed by the name of the database. The formula to use is:

USE DatabaseName;

Here is an example:

USE GovernmentStatistics;

Some of the windows that display databases, like the SQL Server Management Studio, don't update their list immediately if an operation occurred outside their confinement. For example, if you create a database in the query windows, its name would not be updated in the Object Explorer. To view such external changes, you can refresh the window that holds the list.

In SQL Server Management Studio, to update a list, you can right-click its category in the Object Explorer and click Refresh. Only that category may be refreshed. For example, to refresh the list of databases, in the Object Explorer, you can right-click the Databases node and click Refresh.

A namespace is a technique of creating a series of items that each has a unique name. For example, if you start creating many databases, there is a possibility that you may risk having various databases with the same name. If using a namespace, you can isolate the databases in various namespaces. In reality, to manage many other aspects of your database server, you use namespaces and you put objects, other than databases, within those namespaces. Therefore, a namespace and its content can be illustrated as follows:

Notice that there are various types of objects within a namespace.

Within a namespace, you can create objects as you wish. To further control and manage the objects inside of a namespace, you can put them in sub-groups called schemas. Therefore, a schema is a group of objects within a namespace. This also means that, within a namespace, you can have as many schemas as you want:

Notice that, just like a namespace can contain objects (schemas), a schema can contain objects also (the objects we will create throughout our lessons).

To manage the schemas in a namespace, you need a way to identify each schema. Based on this, each schema must have a name. In our illustration, one schema is named Schema1. Another schema is named Schema2. Yet another schema is named Schema_n.

A schema is an object that contains other objects. Before using it, you must create it or you can use an existing schema. There are two types of schemas you can use, those built-in and those you create. When Microsoft SQL Server is installed, it also creates a few schemas. One of the schemas is called sys.

The sys schema contains a list of some of the objects that exist in your system. One of these objects is called databases (actually, it's a view). When you create a database, its name is entered in the databases object using the same name you gave it.

To access the schemas of a database, in the Object Explorer, expand the Databases node, expand the database that will hold or own the schema, and expand the Security node.

To create a schema, right-click Schemas and click New Schema...

This would open the Schema - New dialog box. In the Schema Name text box, enter a one-word name. Here is an example:

After providing a name, you can click OK.

We will see a practical example of creating a schema in Lesson 7.

Inside of a schema, two objects cannot have the same name, but an object in one schema can have the same name as an object in another schema. Based on this, if you are accessing an object within its schema, you can simply use its name, since that name would be unique. On the other hand, because of the implied possibility of dealing with objects with similar names in your server, when accessing an object outside of its schema, you must qualify it. To do this, you would type the name of the schema that contains the object you want to use, followed by the period operator, followed by the name of the object you want to use. From our illustration, to access the Something1 object that belongs to Schema1, you would type:

Schema1.Something1

• Using Microsoft SQL Server Management Studio, create a database named UtilityCompany1 (Accept the default settings)

1. Perform some research on the Internet to find out about different regions of the United States. On a piece of paper, create a list of the regions of the US
2. Connect to the server from the Command Prompt
3. From the Command Prompt, create a database named UnitedStatesRegions1
4. Exit the Command Prompt