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SQL, Database and DBMS Introduction in brief
Access Database and Database Objects
Database Properties
Size of a Database
MS Access Database Objects
Tables
Forms
Reports
Queries
SammaryDatabase Properties
Unlike some other programming environments, Microsoft Access considers a database as a single Windows file with a name. We will eventually learn that this file can contain various objects that actually make up a database. Therefore, a Microsoft Access database is opened as a normal file. And also you can try it what happen when open it two three peoples via network.
Database project has its own properties that you can use to find out some details about your file, to enter some notes about the project, or to give directives to other people who have access to the database. This can be done using a dialog box called the Database Properties. To access it, you can click the Office Button position the mouse on Manage and click Database Properties.
Size of a Database
Access database is primarily a computer file, just like those created with other applications. As such, it occupies an amount of space in the computer memory (RAM). In some circumstances, you should know how much space a database is using. This can be important when you need to back it up or when it is time to distribute it. Also, when adding and deleting objects from your database, its file can grow or shrink without your direct intervention. To check the size of a database, just right-click on the file and click Properties and see file size.
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Compacting a Database |
When you adds objects/ records to DB the file size grows as needed, as well as when you remove objects/data from DB, HDD space was occupying is left empty.
Empty memory cannot be accessed by the computer. This means that the memory space cannot be made available to other applications. To recover this memory space, you can compact / shrink the database. When this is done, the file is shrunk to occupy only the necessary amount of space and free the unused sections.
How to Compact DB in MS Access?
There was two ways to do it.
Compact manually / one time Compact
It is very easy, open the Database click the Office Button, position the mouse on Manage, and click Compact and Repair Database. The database would be compacted behind the scenes.
Compact when close the Application
This occurs every time when you close the database. Click the Office Button, and click Access Options. In the Access Options, in the left list, click Current Database. In the right list, click the Compact on Close check box and click Ok button.
MS Access Database Objects
You can see all these object types in Left Navigation Pane. Select All Access Objects in pane.
Tables
The table is the most fundamental object is a database. It is used to organize a list of values/data. The values can be as simple as some numbers, names of people, apparent insignificant items etc. The first rule is all items should be of the same type (column wise).
E.G.: Mobile Phones (table)
|
Brand |
Model |
Description |
Price |
|
Nokia |
5320 |
Express Music |
25000 |
|
Nokia |
1100 |
Normal |
5000 |
|
Motorola |
C168 |
Color Display |
7000 |
|
Samsung |
HQ-11 |
Camera |
12000 |
Here is the Hierarchy that Microsoft Access uses in breaking down a database.
Hope now you have good idea about Database file and Table.
Field: Fields are the different categories within a Table. Tables usually contain multiple fields.
Example : Mobile Phone Brand
Datatypes:Datatypes are the properties of each field. A field only has one datatype.
Example :
FieldName : Mobile Phone Brand
Datatype : Text
Value : user enterd value for that
Example : Nokia
Forms
A form is the friendliest object that a person uses to interact with a database. It is the primary object used for data entry and analysis.
A form appears a rectangular object with various sections. By default, form may appear with a tab.
Reports
A report provides an object used to print a database tables records. Although you can print tables or forms, reports are customized to be printer friendly. They can perform and display calculations. Once again, Microsoft Access provides wizards to quickly create reports.
Queries
A query is the result of getting or isolating a list of values from a table or another query. Querying is the technique of examining data to create a dependent list. You can perform querying on a table, a form, or a query. Microsoft Access provides various means of performing such an operation visually. As an alternative, Microsoft Access supports SQL that allows you to query a database using code.
There are various ways you create a query in Microsoft Access. Query Wizard helps to crate your query u wish. But there were some limitations, that time you can use Query Design and can be customize query as you wish/expect.
Inside of the GUI in MS Access Query Design window generates SQL statements, do you have good knowledge in SQL you can change SQL statements too.
You can use query as a report source.
You can see these objects in Northwind database. See and do some changes and see how it works.
Database has many properties and users can be change DB properties. When adds objects/ data to DB the file size grows as needed, as well as when you remove objects/data from DB, HDD space was occupying is left empty. That empty memory cannot be access other programs and Database. Compact/shrink is the solution for that. “Manual Compact” and “Compact when close the file” is available two ways to Compact Database in MS Access. The table is the most fundamental object is a database. Forms Reports Queries uses table objects to do their operations.
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