K Hinds Page 1. Information Communication Technology Microsoft Access

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1 Page 1 Information Communication Technology Microsoft Access

2 Page 2 What is a database? A database is a collection of information that is organized so that it can easily be accessed, managed, and updated. It is a repository of information organized through a collection of tables that are related to each other Terminology Table (Relation) - A single store of related information. A table consists of records, and each record is made up of a number of fields. Entity - is a single person, place, or thing about which data can be stored Tuple - is one row or a record in a database table Attributes - are data items that describe an entity. An attribute instance is a single value of an attribute for an instance of an entity. For example, Name and hire date are attributes of the entity EMPLOYEE. "Robert Thompson" and "12 April 1999" are instances of the attributes name and hire date. Primary key - A field that uniquely identifies a record in a table. In a student s table, for instance, a key built from last name + first name might not give you a unique identifier (two or more Jane Does in the school, for example). To uniquely identify each student, you might add a special Student ID field to be used as the primary key. Composite key is a primary key that made up of more than one attribute. Candidate key - A candidate key is one that can identify each row of a table uniquely. Generally a candidate key becomes the primary key of the table. If the table has more than one candidate key, one of them will become the primary key, and the rest are called alternate keys. Alternate/secondary key - is any candidate key which is not selected to be the primary key. Foreign key - A key used in one table to represent the value of a primary key in a related table. While primary keys must contain unique values, foreign keys may have duplicates. For instance, if we use student ID as the primary key in a Students table (each student has a unique ID), we could use student ID as a foreign key in a Courses table: as each student may do more than one course, the student ID field in the Courses table (often shortened to Courses.student ID) will hold duplicate values.

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4 Page 4 Datatypes in Access Text - used to store alphanumeric characters (letters and numbers). Number: this is for fields that use numbers (with or without decimals places). Currency: used to store money values. Date/Time: used to store data or time values. Autonumber: creates automatic numbers. Memo: used to store blocks of text like notes up to characters long. Yes/No: used to store yes or no, true or false values Comparing Manual vs Computerized Database Advantages of a Computerized Database 1. Speed - It can find a specific record or information from among thousands or even a million entries within a second. 2. Compact - Since the database records stored in filing cabinets can be stored in a single floppy disk 3. Flexible - It has the ability to examine information from a number of ways, so you could search for people living in the same city or with persons with the same last names. (It allows you to create ad hoc (impromptu) queries). 4. Views- It allows you to present the same data in multiple views for easy in understanding. 5. Standardization - It reduces the probability of inconsistent data Disadvantages of a Computerized Database Database systems are complex, difficult, and time-consuming to design Substantial hardware and software start-up costs Damage to database affects virtually all applications programs Extensive conversion costs in moving form a file-based system to a database system Initial training required for all programmers and users

5 Page 5 ACTIVITY Create a Database in MS Access Practical component Create a table structure with at least three data types (Alpha numeric, and two others) and populate with at least twenty-five records. Use of wizard is prohibited. Adding two new fields Delete one field Change the field definition for one attribute Sorting a Database Sorting and filtering are tools that let you organize your data. When you sort data, you are putting it in order. Filtering data lets you hide unimportant data and focus only on the data you're interested in. When you sort records, you are putting them into a logical order, with similar data grouped together. As a result, sorted data is often simpler to read and understand than unsorted data. By default, Access sorts records by their ID numbers. However, there are many other ways records can be sorted. For example, the information in a database belonging to a bakery could be sorted in a number of ways: Orders could be sorted by order date or by the last name of the customers who placed the orders. Customers could be sorted by name or by the city or zip code where they live. Products could be sorted by name, category (like pies, cakes, and cupcakes), or price. You can sort both text and numbers in two ways: in ascending order and descending order. Ascending means going up, so an ascending sort will arrange numbers from smallest to largest and text from A to Z. Descending means going down, or largest to smallest for numbers and Z to A for text. The default ID number sort that appears in your tables is an ascending sort, which is why the lowest ID numbers appear first. In our example, we will be performing a sort on a table. However, you can sort records in any Access object. The procedure is largely the same.

6 Page 6 To sort records 1. Select a field you want to sort by. In this example, we will sort by customers' last names. 2. Click the Home tab on the Ribbon, and locate the Sort & Filter group. 3. Sort the field by selecting the Ascending or Descending command. o o Select Ascending to sort text A to Z or to sort numbers from smallest to largest. We will select this in our example because we want the last names to be in A-to-Z order. Select Descending to sort text Z to A or to sort numbers from largest to smallest. 4. The table will now be sorted by the selected field.

7 Page 7 5. To save the new sort, click the Save command on the Quick Access toolbar. After you save the sort, the records will stay sorted this way until you perform another sort or remove the current one. To remove a sort, click the Remove Sort command.

8 Page 8 Generating s A report is a database object that comes in handy when you want to present the information in your database for any of the following uses: Display or distribute a summary of data. Archive snapshots of the data. Provide details about individual records. Create labels. Parts of a report While it is possible to create unbound reports that do not display data, but for the purposes of this article, we ll assume that a report is bound to a data source such as a table or query. The design of a report is divided into sections that you can view in the Design view. Understanding how each section works can helps you create better reports. For example, the section in which you choose to place a calculated control determines how Access calculates the results. The following list is a summary of the section types and their uses: Section How the section is displayed when printed Where the section can be used Header Page Header Group Header At the beginning of the report. At the top of every page. At the beginning of each new group of records. Use the report header for information that might normally appear on a cover page, such as a logo, a title, or a date. When you place a calculated control that uses the Sum aggregate function in the report header, the sum calculated is for the entire report. The report header is printed before the page header. Use a page header to repeat the report title on every page. Use the group header to print the group name. For example, in a report that is grouped by product, use the group header to print the product name. When you place a calculated control that uses the Sum aggregate function in the group header, the sum is for the current group. You can have multiple group header sections on a report, depending on how many grouping levels you have added. For more information about creating group headers and

9 Page 9 Section How the section is displayed when printed Where the section can be used Detail Group Footer Page Footer Footer Appears once for every row in the record source. At the end of each group of records. At the end of every page. At the end of the report. NOTE In Design view, the report footer appears below the page footer. However, in all other views (Layout view, for example, or when the report is printed or previewed), the report footer appears abovethe page footer, just after the last group footer or detail line on the final page. footers, see the section Add grouping, sorting, or totals. This is where you place the controls that make up the main body of the report. Use a group footer to print summary information for a group. You can have multiple group footer sections on a report, depending on how many grouping levels you have added. Use a page footer to print page numbers or perpage information. Use the report footer to print report totals or other summary information for the entire report. Create a report in Access You can create reports for you Access desktop database by following the steps below: Step 1: Choose a record source The record source of a report can be a table, a named query, or an embedded query. The record source must contain all of the rows and columns of data you want display on the report. Step 2: Choose a report tool The report tools are located on the Create tab of the ribbon, in the s group. The following table describes the options:

10 Page 10 Tool Design Blank Wizard Labels Description Creates a simple, tabular report containing all of the fields in the record source you selected in the Navigation Pane. Opens a blank report in Design view, to which you can add the required fields and controls. Opens a blank report in Layout view, and displays the Field List from where you can add fields to the report Displays a multiple-step wizard that lets you specify fields, grouping/sorting levels, and layout options. Displays a wizard that lets you select standard or custom label sizes, as well as which fields you want to display, and how you want them sorted. Step 3: Create the report Click the button for the tool you want to use. If a wizard appears, follow the steps in the wizard and click Finish on the last page. Access displays the report in Layout view. Format the report to achieve the looks that you want: Resize fields and labels by selecting them and then dragging the edges until they are the size you want. Move a field by selecting it (and its label, if present), and then dragging it to the new location. Right-click a field and use the commands on the shortcut menu to merge or split cells, delete or select fields, and perform other formatting tasks. References