A SAMPLE DATABASE |
| Overview |
| Overview | This RLO on a sample database is designed for a corporate training. The training is aimed on employees of several departments and offices in the United Nations. United Nations staff in Administration, Finance, Logistic and other occupations are the target audience of this course. The participants are expected to have some working knowledge on computer and general applications such as word processing and spreadsheets. This training helps the participants building a concept about database, its components and structure, creating a simple database, table, form and report. After completion of this training, the staff can be able to organize the data records in their daily works. This document is compliant with CanCore standards regarding Learning Object Metadata (LOM). |
| What is a database? |
| What is a database? |
A database is a organized collection of data in a related subject. Since you've used computer and have some knowledge of wordprocessing and spreadsheets, chances are you've already had some experience with a database. Simply put, databases are used to store and manage information. Databases are probably one of the most common uses of computers, and are available on just about every type of computer. You probably deal with many different databases everyday without realizing it. Anytime you lookup a phone number in directory, do a transaction at the bank, pay for something with a credit card, or purchase something on the Web, you're using a database. Databases are not specific to computers. Examples of non-computerised databases abound: phone book, dictionaries, almanacs, etc. (although in actuality these are examples of printed reports generated from databases). One classic database example is the Rolodex card file found on many desktops. It is used to store contact information for people and businesses you deal with on a regular basis. One popular feature of the Rolodex is the ability to separate your contacts alphabetically. One problem with this solution is that once you've decided to organise your Rolodex by, for example, Last Name, it's very difficult to find someone by Company Name, or First Name, or any other piece of information contained on a business card. Electronic databases were designed to overcome this problem, and to take advantage of the enormous power available in modern computers. Computers are designed to process information using a variety of tools, or applications. Each application is designed to solve a particular task; word-processing, number crunching (spreadsheet), e-mail, and web surfing. In addition to these common tasks, computers are most often used for storing and manipulating data, the task of a database. Some databases have specialised interfaces for specific tasks, such as Accounting, CRM (Customer Resource Management), Inventory Control, Order Entry, etc. It's safe to say that just about every business has at least one use for a database application. |
| Database Examples |
| Database Examples |
We can see many databases in our daily lives. Some examples of databases:
The list can grow long. |
| Database Development Environment (Database Management System) |
| Database Development Environment (Database Management System) |
While a database is simply the structured collection of data (usually handled by a database engine), applications that utilise information contained in databases are typically created with a database development environment. These development tools are unlike traditional programming environments in that they provide tools to create applications that allow users to manage data easily, without having to deal with the low-level details normally associated with traditional programming (such as memory management, etc.) Instead, database development environments typically have tools for creating forms using a form editor, some kind of scripting environment or specialised high-level language for controlling the interface and access to the database engine, and other high-level tools specifically designed for manipulating information. While most large databases (ORACLE, Sybase, etc) are only database engines, they are commonly accessed from a separate "client" application via a special database access language. Integrated database development environments usually contain their own (often proprietary) database engine, making the creation of self-contained applications much easier. However, if a database application requires access to an external database engine using a database access language (such as SQL or ODBC), then this is also possible. |
| Relational Database |
| Relational Database |
When talking about databases, the term "relational" is often heard. This is used to describe database engines that are able to work with more than group (or table) of information at the same time. This allows for much efficiency when dealing with most types of data. For example, in the above Rolodex example, say that more than one person worked at the same Company. If the company address changed, each card (or record) in the People file (table) would have to be changed. With a relational database, a second table which contained just Company information (one company per record) would be created, and each person would link (or relate to) a single company. When a field in the Company record changes, the new data is immediately available to any related Contact records. Examples of such database development environments are Microsoft Access, SQL Server and oracle. These tools allow the creation of sophisticated commercial level applications with custom interfaces, and complex reports; the main difference is the ease in which solutions can be created, and scaled as your needs grow. |
| Understanding Tables, Fields, and Records |
| Understanding Tables, Fields, and Records |
In a database, data is organised and stored in data structures known as tables. A table contains information about one thing. For example, a contacts table would store information about contacts, and only about contacts. The data stored in a table is divided and structured into attributes that comprise the thing for which the table is storing data. For example, a contacts table would need to store at least the following attributes of a contact: First name, Last name, Address, Zip Code. In the resulting data structure, the term "field" is used in place of "attribute". One way of visualizing the data stored in a table is to think of a spreadsheet, since a spreadsheet presents data in a tabular format comprised of columns and rows. In this case, the spreadsheet is the equivalent of a table, and the columns are the attributes or fields. In a table, or a spreadsheet, each row contains the set of data for all attributes/fields for one instance of the thing for which the table is storing data. For example, in a contacts table, a row would be the set of data attributes for one contact- the contact_s First name, Last name, Address etc. The set of attributes for one instance of the thing for which the table is storing data, is known as a record. So in a database we have records of data, comprised of fields, stored in tables. Records are written to disk for permanent storage. |
| A database sample |
| A database sample |
Following is a database of employees working for the UN in Kosovo. There are two tables - one is STAFF that contains data specific to staff and another is DEPARTMENTS that stores data related to departments. These tables are related. The table STAFF has a column(field) called Department that links the records in STAFF to DEPARTMENTS. Similarly, DEPARTMENTS has a column called Chief_ID that links records with the STAFF table.  |
| Primary and Foreign Key |
| Primary and Foreign Key |
The power of a relational database system such as Microsoft Access comes from its ability to quickly find and bring together information stored in separate tables using queries, forms, and reports. In order to do this, each table should include a field or set of fields that uniquely identifies each record stored in the table. This information is called the primary key of the table. Once you designate a primary key for a table, the DBMS will prevent any duplicate or Null values from being entered in the primary key fields. IDNumber in STAFF and Department in DEPARTMENTS are the primary key fields. Foreign Key: One or more table fields (columns) that refer to the primary key field or fields in another table are known as Foreign Keys. A foreign key indicates how the tables are related. The field Departments in STAFF and Chief_ID in DEPARTMENTS are the foreign keys. |
| Creating a Database in Microsoft Access |
| Creating a Database in Microsoft Access |
Microsoft Access provides two methods to create an Access database. You can use a Database Wizard to create in one operation the required tables, forms, and reports for the type of database you choose - this is the easiest way to start creating your database. Or you can create a blank database and then add the tables, forms, reports, and other objects later - this is the most flexible method, but it requires you to define each database element separately. Either way, you can modify and extend your database at any time after it has been created. Create a database by using a Database Wizard:
Note: You can't use the Database Wizard to add new tables, forms, or reports to an existing database. Create a database without using a Database Wizard
The Database window appears, and you can create the objects that you want in your database. |
| Create a table (Microsoft Access) |
| Create a table (Microsoft Access) |
Create a table by using the Table Wizard:
Create a table in Design view:
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| Creating a Form (Microsoft Access) |
| Creating a Form (Microsoft Access) |
A form is a type of a database object that is primarily used to enter or display data in a database.
Create a form Using Design View: You create a basic form and customize it in Design view to suit your requirements.
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| Creating a Report (Microsoft Access) |
| Creating a Report (Microsoft Access) |
A report is a type of a database object that is primarily used to display data in a database. Using Report Wizard:
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| Quiz |
| Quiz |
End User Training: Questions:
Answers:
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| About Reusable Learning Objects (RLOs) |
| About Reusable Learning Objects (RLOs) |
Introduction: This learning module is compliant with CanCore standards regarding Learning Object Metadata (LOM). CanCore is a set of best practices for interpreting and implementing IEEE LOM standards. The CanCore initiative has been coordinated by Athabasca University and funded by Industry Canada/CANARIE, Alberta Learning, Netera Alliance, TeleCampus.edu, and the Electronic Text Centre at the University of New Brunswick. CanCore is used throughout the U.S., Canada, U.K. and France. Some examples include Athabasca University (http://adlibx.athabascau.ca/ADLib/LOR/args0/ADLib/args1/Home/?text=about), BC Campus (http://www.bccampus.ca), CELTS (China), Desire2Learn (http://www.desire2learn.com), Eisenhower National Clearinghouse (http://www.enc.org/), Canadian Treasury Board, National Science Digital Library (http://www.nsdl.org/), and UK LOM Core (http://www.cetis.ac.uk/profiles/uklomcore/). Meta data refers to information that describes the characteristics of the learning object. IEEE (p1484) identifies the following LOM categories: General, Life Cycle, Meta-Meta Data, Educational, Technical, Rights, Relation, Annotation and Classification. The IEEE standard does not define how a learning technology system will represent metadata. The purpose of the standard is to facilitate interoperability. By providing a common taxonomy, users can more easily search, evaluate, acquire, catalog, inventory and use learning objects across organizations and cultures. Learning technology systems should be able to automate this process. A sample of metadata, implemented using the CanCore LOM standard, is illustrated in the Metadata section of this document. (The underlying XML of this metadata can be found in RLO.XML). For a detailed description of the CanCore standard, complete with definitions and examples, see http://www.cancore.ca/en/dynamic/. A Reusable Learning Object (RLO) is an entity, digital or non-digital, that may be used and reused for educational purposes. RLO's (also known as lessons) are viewed as data structures made up of smaller objects called Reusable Information Objects (RIO's, also known as topics). These RIO's may be reassembled as desired to provide customized RLO's. The following is a sample hierarchy developed by Cisco for the Canadian Navy RLO project:
The document you are currently reading (i.e. entitled A Sample Database) has been implemented as an RLO, and each of the topics (including this topic of About Reusable Learning Objects (RLO)) have been implemented as RIO's. XML has been chosen as the format to store content, with DTD to enforce data structure, and XSL to define presentation format. Some of the advantages of this approach are as follows:
RDF is another good alternative. RDF represents data using a directed graph structure, whereas XML represents data using a tree structure. Just as a tree strcture is one possible configuration of a directed graph, XML is one possible syntax of RDF. Design: This learning module contains the following files:
When RLO.XML, RLO.XSL, RLO_Content.XSL and RLO.DTD are placed in the same directory as BuildHTML.BAT and BuildHTML.BAT is executed, the final presentation in HTML format is created. Contents.HTML is the table of contents and RLO.HTML is the learning material itself. There is also a subdirectory called Images which contains all of the GIF files to which the hyperlinks in RLO.HTML point. In RLO.XML, educational content is organized using the following tags:
This design approach helps to organize content, so that it may easily be referenced or reused, while still providing curriculum designers the flexibility to organize it as they wish. Material may be reorganized or combined with other material by simply copying and pasting "RIO" sections of text from one XML document to another. The XSL file does all the work of modifying the presentation format. The RLO.XSL file is the design template for the final HTML presentation. As long as the XML file follows the above structure, a single XSL file will work on all XML files, regardless of their content. Thus, there is no hard-coding of content into the XSL file. All references to content are dynamic, not static. This allows users to enforce a common look and feel for all presentation materials, without having to change each individual module. |
Summary |
| Summary |
Database Concepts: A database is a organized collection of data in a related subject.Anytime you lookup a phone number in directory, do a transaction at the bank, pay for something with a credit card, or purchase something on the Web, you're using a database. Databases are not specific to computers. Examples of non-computerised databases abound: phone book, dictionaries, almanacs, etc. Electronic databases were designed to overcome the sorting, filtering and other data management problems in manual databases, and to take advantage of the enormous power available in modern computers. Some examples of databases are: purchases from the supermarket, purchases using a credit card, booking a holiday at the travel agents, using the local library, taking out insurance, renting a video, using the Internet, studying at university, etc. The applications that utilise information contained in databases are typically created with a database development environment. Database development environments typically have tools for creating forms using a form editor, some kind of scripting environment or specialised high-level language for controlling the interface and access to the database engine, and other high-level tools specifically designed for manipulating information. The term 'relational' is used to describe database engines that are able to work with more than group (or table) of information at the same time. This allows for much efficiency when dealing with most types of data. Examples of such database development environments are Microsoft Access, SQL Server and oracle. These tools allow the creation of sophisticated commercial level applications with custom interfaces, and complex reports. Table, Record and Field: In a database, data is organised and stored in data structures known as tables. A table contains information about one thing. For example, a contacts table would store information about contacts, and only about contacts. The data stored in a table is divided and structured into attributes that comprise the thing for which the table is storing data. For example, a contacts table would need to store at least the following attributes of a contact: First name, Last name, Address, Zip Code. In the resulting data structure, the term "field" is used in place of "attribute". In a table, each row contains the set of data for all attributes/fields for one instance of the thing for which the table is storing data. For example, in a contacts table, a row would be the set of data attributes for one contact: the contact's First name, Last name, Address etc. The set of attributes for one instance of the thing for which the table is storing data, is known as a record. So in a database we have records of data, comprised of fields, stored in tables. Records are written to disk for permanent storage. Primary and Secondary Key: The power of a relational database system such as Microsoft Access comes from its ability to quickly find and bring together information stored in sePARAGRAPHte tables using queries, forms, and reports. In order to do this, each table should include a field or set of fields that uniquely identifies each record stored in the table. This information is called the primary key of the table. Once you designate a primary key for a table, the DBMS will prevent any duplicate or Null values from being entered in the primary key fields. One or more table fields (columns) that refer to the primary key field or fields in another table are known as Foreign Keys. A foreign key indicates how the tables are related. Creating a Database, Table, Form, Report in Microsoft Access: Microsoft Access provides two methods to create an Access database. You can use a Database Wizard to create in one operation the required tables, forms, and reports for the type of database you choose: this is the easiest way to start creating your database. Or you can create a blank database and then add the tables, forms, reports, and other objects later: this is the most flexible method, but it requires you to define each database element separately. Either way, you can modify and extend your database at any time after it has been created. Similarly, we can create tables, forms and reports in Microsoft Access by either using the wizards or designing ourselves. About Reusable Learning Objects (RLO): This learning module is compliant with CanCore standards regarding Learning Object Metadata (LOM). CanCore is a set of best practices for interpreting and implementing IEEE LOM standards. A Reusable Learning Object (RLO) is an entity that may be reused for educational purposes. RLO's (or lessons) are made up of smaller objects called Reusable Information Objects (RIO's, or topics). These RIO's may be reassembled to provide customized learning content. e.g.: Curriculum, Unit, Module, Lesson (RLO), Topic (RIO). This document uses XML as metadata format, with DTD to enforce data structure, and XSL to define presentation format. Advantages include international standardization, strength in describing educational metadata, separation of content from presentation format, machine readability, enforcement of structure, and human readability of XML. RDF is another strong alternative. The IEEE standard defines a conceptual data schema for learning metadata, although it does not define how a learning technology system will represent metadata. The purpose is to facilitate interoperability by providing a common taxonomy. Cancore provides guidance in interpreting and implementing these standards. The metadata associated with this document is contained within a "Metadata" tag in the RLO.XML file. |
Metadata |
| Metadata |
General:
Last Modified:
Title:
Language:
Description:
Structure: Aggregation Level: Key Words: Meta Meta Data:
Meta Meta Data Identifier: Contributor Role: Contributor Entity:
Contribution Date:
Meta Data Schema: Meta Data Language: Technical:
Technical: Educational:
Learning Resource Type: Intended End User Role: Educational Context:: Typical Age Range: Rights:
Rights Cost: Copyright And Other Restrictions: Rights Description: Relation:
Kind of Relation: Relation Resource: Classification:
Classification Purpose: Taxon Path source: Taxon: |