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Fundamentals of Database. CVSL Grade VII & VIII. Topics to be covered . “ what is a database;” Understand the difference between data and information; What is the purpose of a database system; Database definitions and fundamental building blocks;. What is a database.
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Fundamentals of Database CVSL Grade VII & VIII
Topics to be covered • “what is a database;” • Understand the difference between data and information; • What is the purpose of a database system; • Database definitions and fundamental building blocks;
What is a database A database is any organized collection of data.Some examples of databases you may encounter in your daily life are: • a telephone book • T.V. Guide • airline reservation system • motor vehicle registration records • Forms you are filling for Admission
Data vs. information:What is the difference? • What is data? • Data can be defined in many ways. Information science defines data as unprocessed information. • What is information? • Information is data that have been organized and communicated in a coherent and meaningful manner. • Data is converted into information, and information is converted into knowledge. • Knowledge; information evaluated and organized so that it can be used purposefully.
What is the ultimate purpose of a database management system? Is to transform Data Information Knowledge Action
Why do we need a database? • Keep records of • Students • Staff • Library • Stocks • To keep a record of activities and interventions; • Keep sales records; • Develop reports; • Perform search • Tracking a particular record
Example of Database • Ms Access • FileMaker • Lotus Notes • Oracle • SQL Server
What is the purpose of the database ? • A database management system (DBMS) provides you with the software tools you need to organize that data in a flexible manner. • It includes tools to add, modify or delete data from the database, ask questions (or queries) about the data stored in the database and produce reports summarizing selected contents.
Some Important Definitions • A File: A group or collection of similar records, like Student File, American History 1850-1866 file, Basic Food Group Nutrition File • A field: one category of information, i.e., Name, Address, Semester Grade, Academic topic • A record: one piece of data, i.e., one student's information, a recipe, a test question • A layout: a design for a database that contains field names and possibly graphics.
Fundamental building blocks Tables comprise the fundamental building blocks of any database. If you're familiar with spreadsheets, you'll find database tables extremely similar. Take a look at this example of a table sample database: The table above contains the employee information for our organization -- characteristics like name, date of birth and title. Examine the construction of the table and you'll find that each column of the table corresponds to a specific employee characteristic (or attribute in database terms). Each row corresponds to one particular employee and contains his or her information. That's all there is to it! If it helps, think of each one of these tables as a spreadsheet-style listing of information.
What is Microsoft Access Used For? Microsoft Access is an information management tool that helps you store information for reference, reporting, and analysis. Microsoft Access can help you overcome the limitations found when trying to manage large amounts of information in Microsoft Excel or other spreadsheet applications.
What is Microsoft Access made up of? • The Microsoft® Access Database is made up of 7 major components: • Tables; • Relationships; • Queries; • Forms; • Reports; • Macros; • Modules.
Tables • The tables are the backbone and the storage container of the data entered into the database. • The tables that contain data look a bit like a table in Microsoft® Word or a Microsoft® Excel Spreadsheet, when opened. They have columns and rows as does a table in Microsoft® Word and an Excel worksheet. Each of the columns will have a field name at the top and each of the rows will represent a record. • As an example:
Primary Key • The primary key of a relational table uniquely identifies each record in the table. • This can be a unique identification number such as a Medicare number, Employee ID number, Pension number, etc.: • A primary key cannot contain duplicate values, e.g. a person’s last name is not suitable as a primary key as there is often more than one person with the same last name; • A primary key cannot contain null values, therefore a field such as a phone number is not suitable, as you may not know the person’s phone number when you first enter them into the database; • Also, if the information contained in the Primary Key is likely to be altered, then it is best to avoid this field as well. • If a unique identifier cannot be identified (which is more than likely), you can add a field, which will automatically increase sequentially by one, thus providing the record with a unique identifier.
Data type • The data type of a programming element refers to what kind of data it can hold and how that data is stored. Data types apply to all values that can be stored in computer memory or participate in the evaluation of an expression. • Example • Name – hold alphabets • Marks – number
MS ACCESS DATATYPES • AutoNumber Numbers that are automatically generated for each record. • Currency Monetary values. • Date/Time Dates and times. • Hyperlink Hyperlinks, such as e-mail addresses. • Memo Long blocks of text and text that use text formatting. A typical use of a Memo field would be a detailed product description. • Number Numeric values, such as distances. Note that there is a separate data type for currency. • OLE Object OLE objects, such as Word documents. • Text Short, alphanumeric values, such as a last name or a street address. • Yes/No Boolean values.
You can view your Microsoft Access tables in two different views - Datasheet view and Design view. • Datasheet view : Access allow you to view the contents of a table. When opened, you will see something similar to a spreadsheet, with columns of data with the field names identifying each column, whilst each row is a single record within the table. This is called the datasheet view. • 'Design view' where you see the structure of the table rather than the contents. It shows the field names and their datatype. From design view you can add and delete fields within the table, although you have to be careful with deleting the primary key in the table as that would cause problem with data integrity.
Query • A query is a request for information from a database which matches a set of criteria. • You use queries all the time when you use a search engine such as Google. You type in the term that you want some information about and click 'search'. The search engine looks through its database and displays a list of results which match the term that you used.
Other objects of Ms Acess • Forms provide non-technical users the ability to add data to your database. • Reportreport is a document (paper or electronic) that presents data in an easy-to-read, professional format. Reports can be created within database applications such as Access. In this case the results of database queries are presented in an attractive format, with headings, fonts and colours designed to enhance understanding of the data. • A "macro" refers to a set of actions that can be run automatically, and on demand. You could make a macro run when a user presses a certain key, or you could make a macro run everytime your database is opened. • Module A module is a collection of user-defined functions, subroutines, and global variables written in VBA code. These objects can then be used/called from anywhere in your Access database.
