Database Concepts and Terminologies

Database Concepts and Terminologies

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  PRESENTER OUSMAN FAAL Database ConceptAnd Terminology
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  What is aDatabase  Its an organized collection of information which can easily be retrieve.  Telephone Book  Mailing List  Address List  Set of data related for a specific purpose or topic.  It includes tools needed to work with data, such as:  Sorting  Filtering  Extracting  Summarizing
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  Database Terminology  Table A list of related information in columns and rows  Each Row in a table is considered a Record (your information in the phone book is a record)  Each Column in the table is a category or a Field (a column of phone numbers in the phone book would be considered field)  One item of data, such as your phone number in the phone book is called a Data value
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  Query  A queryis a database object that can be used to extract or show information in Datasheet view.  You can use a query to show all customers who has ordered a certain product.  A query can get its data from one or more tables, from existing queries, or from a combination of the two. The tables or queries from which a query gets its data are referred to as its record source.
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  Forms  A formis a database object that you can use to enter, edit, or display data from a table or a query.  For example, certain users might need to see only several fields in a table with many fields. Providing those users with a form that contains just those fields makes it easier for them to use the database.  A visually attractive form makes working with the database more pleasant and more efficient, and it can also help prevent incorrect data from being entered.
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  Report  A reportis another database object which can be use to summarize information from a table or query.  Reports can be very useful when you have already create queries from tables and you want to analyze or summarize those queries so that they can be ready for printing. And you can be able to choose which fields you want in your report.
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  Macros  A macrocan be use to create an action or set of actions that can be use to automate a task.  You can create a macro to perform a specific series of actions.  macros can be contained in macro objects or they can be embedded into the forms and reports.
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  Relational Database Concept Ms Access is a Relational Database  Contain multiple Tables  Each Table pertains a specific topic  We just need to add fields to each table that will contain data that will uniquely identifies each record. Name Address City Phone# Customers Account# Account Type Date Opened Balance Accounts
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  Primary Keys  Aprimary key is a field or set of fields in your table that provide Ms Access with a unique identifier for every row.  In a relational database you divide your information into separate tables. You then use table relationships and primary keys to bring the information together.  Each table in a database must have a primary key before it can be related to another table.
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  Primary Keys andForeign Keys • For example, a Customer ID field in the Customers table might also appear in the Accounts table. In the Customers table, it is the primary key. In the Accounts table it is called a foreign key. A foreign key, simply stated, is another table's primary key. Primary Table Related Table Customer ID (*) Name Address City Phone# Customers Customer ID Account# (*) Account Type Date Opened Balance Accounts
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  Types Of Relationship One-to-One relationship exist when a primary record from the primary table has only one related record in the related table.  You might use a one-to-one relationship to divide a table with many fields, to isolate part of a table for security reasons, or to store information that applies only to a subset of the main table
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   One-to-Many relationshipexist when a primary record from the primary table is related to many records in the related table.  One customer can have many accounts  One customer can order many products  One person may have many phone numbers  A person may have multiple e-mail addresses  A music CD usually has many songs
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   Many-to-Many relationshipexist when a primary record from the primary table is related to many records in the related table AND a related record in the related table is also related to many records in the primary table.  People can have many address; and addresses may have many people  A single order can include more than one product. On the other hand, a single product can appear on many orders.  A supplier can carry many products; and a single product may be available from many suppliers  A student takes many classes; and each class has many students