EOC Summary

1. What is a database, and why is it beneficial to use databases? Databases are electronic collections of related data that can be organized so that it can be more easily accessed and manipulated. Properly designed databases cut down on data redundancy and duplicate data by ensuring relevant data is recorded in only one place. This also helps eliminate data inconsistency, which comes from having different data about the same transaction recorded in two different places. And when databases are used, multiple users can share and access information at the same time. Databases are used any time complex information needs to be organized or more than one person needs to access it. In these cases, lists (which are used to keep track of simple information) are no longer efficient.

2. What components make up a database? The three main components of a database are fields, records, and tables. A category of information in a database is stored in a field. Each field is identified by a field name, which is a way of describing the field. Fields are assigned a data type that indicates what type of data can be stored in the field. Common data types include text, numeric, computational, date, memo, object, and hyperlink. A group of related fields is called a record. A group of related records is called a table or file. To keep records distinct, each record must have one field that has a value unique to that record. This unique field is called a primary key (or a key field).

3. What types of databases are there? The three major types of databases currently in use are relational, object-oriented, and multidimensional databases. Relational databases are characterized by two-dimensional tables of data in which a common field is maintained in each of two tables and the information in the tables is linked by this field. Object-oriented databases store data in objects, not in tables. The objects also contain instructions about how the data is to be manipulated or processed. Multidimensional databases represent data in three-dimensional cubes to enable faster retrieval of information from the database.

4. What do database management systems do? Database management systems (DBMSs) are specially designed application software (such as Oracle or Microsoft Access) that interacts with the user, other applications, and the database itself to capture and analyze data. The main operations of a DBMS are creating databases, entering data, viewing (or browsing) data, sorting (or indexing) data, extracting (or querying) data, and outputting data. To extract records from a database, you use a query language. Almost all relational databases today use structured query language, or SQL. However, most DBMSs include wizards that enable you to query the database without learning a query language. The most common form of output for any database is a printed report.

5. How do relational databases organize and manipulate data? Relational databases operate by organizing data into various tables based on logical groupings. Because not all of the data in a relational database is stored in the same table, a methodology must be implemented to link data between tables. In relational databases, the links between tables that define how the data is related are referred to as relationships. To establish a relationship between two tables, both tables must have a common field (or column). Once linked, information can be drawn from multiple tables through the use of queries (for on-screen viewing of data) or report generators (used to produce printed reports).

6. What are data warehouses and data marts, and how are they used? A data warehouse is a large-scale electronic repository of data that contains and organizes in one place all the relevant data related to an organization. Data warehouses often contain information from multiple databases. Because it can be difficult to find information in a large data warehouse, small slices of the data warehouse, called data marts, are often created. The information in data marts pertains to a single department within the organization, for example. Data warehouses and data marts consolidate information from a wide variety of sources to provide comprehensive pictures of operations or transactions within a business.

7. What is an information system, and what types of information systems are used in business? Information systems are software-based solutions that are used to gather and analyze information. Information systems fall into one of four categories. An office support system is designed to assist employees in accomplishing their day-to-day tasks and to improve communications. A transaction processing system (TPS) is a system that is used to keep track of everyday business activities. A management information system (MIS) provides timely and accurate information that enables managers to make critical business decisions. A decision support system (DSS) is a system designed to help managers develop solutions for specific problems.

8. What is data mining, and how does it work? Data mining is the process by which large amounts of data are analyzed to spot otherwise hidden trends. Through processes such as classification, estimation, affinity grouping, clustering, and description (visualization), data is organized so that it provides meaningful information that can be used by managers to identify business trends.