Introduction and Conceptual Modeling Database Introduction and Conceptual Modeling

Database Types of Databases and Database Applications Outline: Types of Databases and Database Applications Basic Definitions. Typical DBMS Functionality Example of a Database Main Characteristics of the Database Approach Database Users Categories of End-users Advantages of Using the Database Approach Additional Implications of Using the Database Approach

Types of Databases and Database Applications Numeric and Textual Databases Multimedia Databases Geographic Information Systems (GIS) Data Warehouses

Basic Definitions Database: A collection of related data. Data: Known facts that can be recorded and have an implicit meaning. Mini-world: Some part of the real world about which data is stored in a database. For example, student grades and transcripts at a university. A software package/ system to facilitate the creation and maintenance of a computerized database. Database System: The DBMS software together with the data itself. Sometimes, the applications are also included.

Example of a Database (with a Conceptual Data Model) Mini-world for the example: Part of a School environment. Some mini-world entities: STUDENTs COURSEs SECTIONs (of COURSEs) (academic) DEPARTMENTs INSTRUCTORs

Example of a Database (with a Conceptual Data Model) Some mini-world relationships: SECTIONs are of specific COURSEs STUDENTs take SECTIONs COURSEs have prerequisite COURSEs INSTRUCTORs teach SECTIONs COURSEs are offered by DEPARTMENTs STUDENTs major in DEPARTMENTs

Typical DBMS Functionality Define a database : in terms of data types, structures and constraints Construct or Load the Database on a secondary storage medium Manipulating the database : querying, generating reports, insertions, deletions and modifications to its content Concurrent Processing and Sharing by a set of users and programs – yet, keeping all data valid and consistent

Typical DBMS Functionality Other features: Protection or Security measures to prevent unauthorized access “Active” processing to take internal actions on data Presentation and Visualization of data

Typical DBMS Functionality A Database program lets you: Store Information A database stores lists of information that are related to a particular subject or purpose. A database stores personal information or business information, a database is also makes it easy to update, organize, and delete information. Find Information You can easily and instantly locate information stored in a database.

Typical DBMS Functionality Analyze and Print Information you can perform calculates on information in a database. For example, you could calculate what percent of your total sales comes from the state of Texas. You can also present information in a professional-looking printed report. Manage Information Databases make it easy to work with and manage huge amounts of information.

Typical DBMS Functionality Share Information most database programs (include Microsoft Access) allow more than one user to view and work with the same information at once. Such databases are called Multi-user databases.

Extending Database Capabilities New functionality is being added to DBMSs in the following areas: Scientific Applications Image Storage and Management Audio and Video data management Data Mining Time Series and Historical Data Management The above gives rise to new research and development in incorporating new data types, complex data structures, new operations and storage and indexing schemes in database systems.

Microsoft Access 2000 Databases usually consist of several parts. A Microsoft access database may contain up to six different database object types as follows:

Microsoft Access 2000 Tables Tables store a database’s data in rows (records) and columns (Fields). Queries Queries ask a question of data stores in a table. E.g. query might only display customers who are from Texas. Forms Forms are custom screen that provide an easy way to enter and view data in a table or query.

Microsoft Access 2000 Report Reports present data in a table or query in a printable format. Pages A special type of webpage designed for viewing and working with Microsoft access data from an intranet or over the internet. Macros Macros help you perform routine tasks by automating them into a single command.

Microsoft Access 2000 Loading the Microsoft Access Program: Start

Microsoft Access 2000 Components of a Table

Microsoft Access 2000 Components of a Table : A field: a specific type of information, such as a last name of your employee. A Field Name: A name that identifies the information in a field. A record: A collection of information about one person or thing.

Microsoft Access 2000 To open a table in design view: Select the table and click design view. Data Types: Numeric: which means it contains only numbers. Character text: numbers, letters and other symbols can be entered. Date/Time: Date and time is entered. Boolean / logical: which allows Y/N or T/F

Microsoft Access 2000 Data types in access: 1. Text: Stores text, numbers, or a combination of both, up to 255 characters long. Text fields are the most common of all data types. 2. Memo: stores long text entries – up to 64,000 characters long (equivalent to 18 pages of text). Use memo fields to store notes or anything else that requires lots of space. 3. Number: stores numbers that can be used for calculation. 4. Date/Time: stores dates/times or both. 5. Currency: stores numbers and symbols that represent money.

Microsoft Access 2000 6. Auto number: Automatically fills in a unique number for each record. Many tables often contain an auto-number field that is also used as their primary key. 7. Yes/No: stores only one of two values, such as yes or no, true of false. 8. OLE object: stores objects created in other programs such as a graphic, excel sheet, or work documents. 9. Hyperlink: stores clickable links to files on your computer or on the network of to WebPages on the internet. 10. Lookup wizard: a wizard that helps you create a field whose values are selected from a table, query or a preset list of values.

Microsoft Access 2000 Entering data to a table: There are two ways of entering data into a table: 1- Key in data directly into the table after opening it. 2- Using a form. Make sure to proof-read the data entered for errors.

Microsoft Access 2000 Working with Query: A query is to ask a question of the information in a table and then retrieve and display the results. There are two ways to create a query: Create a query in Design View. Create a query using wizard.

Microsoft Access 2000 Creating a query in Design View: Double click “Create a query in design view”. The “Show Table” dialog box appears, select the table you want to query. Then close the box. Double click on the fields you want to appear on your query. Set the criteria by inserting a criteria operator. Save the query. Click on it to display the results.

Microsoft Access 2000

Microsoft Access 2000 Here is a smattering of criteria operators and examples to get you started:

Finds records equal to MN Operator Example Description = =”MN” Finds records equal to MN <> <>”MN” Finds records not equal to MN. < <10 Finds records less than 10 <= <=10 Finds records less than or equal to 10 > >10 Finds records greater than 10 >= >=10 Finds records greater than or equal to 10 BETWEEN Between 1/1/99 AND 12/31/99 Finds records between 1/1/99 and 12/31/99 LIKE Like “S*” Finds text beginning with the letter S. you can use LIKE with wildcards such as *.

Microsoft Access 2000 A criteria is used to display a certain type of information on your query taken from the table. E.g. display only USA countries. Criteria And OR rows defines one or set of limiting conditions. -To define condition with AND insert the criteria on the same row. -To define the condition with OR insert the criteria on the first and second row.

Microsoft Access 2000 Query to retrieve record which contain “EU” or “England” country you must insert the criteria on the first and second row. . to

Microsoft Access 2000 To make Query to retrieve record which contain “EU” and “England” country you must insert criteria in the same row.

Microsoft Access 2000 Sorting a Query: Tables normally display records in the order they were entered. Instead of working with table’s jumbles record order, you can create a simple query that sorts the table information and presents it in an ordered, easy-to-read display. You can sort records alphabetically, numerically, or chronically (by date) in ascending (A to Z) or descending (Z to A) order. You can also sort by multiple fields.

Microsoft Access 2000 To sort the query click the Sort row for the field you want to use to sort the query and select either ascending or descending.

Report Report is printable format that represent data in a table or query. Every report most contains : Title : page header Field name. Field data.

Report To create the report In the Database window, click Reports, and then double-click Create report by using wizard. In the Report Wizard, go to the Tables/Queries list, and then select Table: Products. Click >> to move all of the available fields from the Available Fields list to the Selected Fields list, and then click Next.

Report To accept the default grouping levels, click Next. Select Product Name from the first drop-down list, and then click Next. Select the Columnar layout option, ensure that the Adjust the field width so all fields fit on a page option is selected, and then click Next. Select the Soft Gray style, and then click Next. In the What title do you want for your report box, type the required title, and then click Finish.

Alter the data and update the report To alter your report : Right click on your report name then select design view. In design view screen you can modify the size and location any field and you can add new field name and his data field which is calculated at run time

Adding new field at run time For example: If I ask you to add cost as new field to your report for calculate the Price * item 1.From toolbar select text box and drop it in the specific location, this text box already has Label and box

Adding new field at run time 2. Change the label to Cost 3. Write =item*price in the box 4. Press Enter ,the function will be change automatically to =[item]*[price] 5. Save your report. If u see small green triangle at the left side of the text box that is means there is error. Note :your table already has item and price as fields but its doesn't has cost field.