Module #1: Database Systems (Review)

What is a Data Dictionary?

A DBMS component that stores metadata—data about data. Thus, the data dictionary contains the data definition as well as its characteristics and relationships. A data dictionary may also include data that is external to the DBMS.

What is a Field? (File Terminology)

A character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data. - In the Image, the Field is each individual column.

What is a Database Management System?

A collection of programs that manages the database structure and controls access to the data stored in the database. Simply Explained: - In a sense, a Database resembles a very well-organized electronic filing cabinet in which powerful software (the DBMS) helps manage the cabinet's contents.

What is a File? (File Terminology)

A collection of related records. For example, a file might contain data about the students currently enrolled at Gigantic University. -In the Image, the File is the entire spreadsheet.

What is a Data Anomaly?

A data abnormality in which inconsistent changes have been made to a database. Example: An employee moves, but the address change is not corrected in all files in the database.

What is Structural Dependence?

A data characteristic in which a change in the database schema affects data access, thus requiring changes in all access programs. Simply Explained: Access to a file is dependent on its structure. Example: Adding a customer date-of-birth field to the CUSTOMER. Given this change, none of the previous programs will work with the new CUSTOMER file structure.

What is Structural Independence?

A data characteristic in which changes in the database schema do not affect data access. Simply Explained: When you can change the file structure without affecting the application's ability to access the data. Example:

What is Data Dependence?

A data condition in which data representation and manipulation are dependent on the physical data storage characteristics.

What is Data Management?

A discipline that focuses on the proper generation, storage, and retrieval of data.

What is a Record? (File Terminology)

A logically connected set of one or more fields that describes a person, place, or thing. For example, the fields that constitute a record for a customer might consist of the customer's name, address, phone number, date of birth, credit limit, and unpaid balance. - In the Image, the Record is each individual row.

What is a Query Language?

A nonprocedural language that is used by a DBMS to manipulate its data. An example of a query language is SQL. Example:

What is an End-User?

A person who ultimately uses or is intended to ultimately use a product.

What is Structured Query Language (SQL)?

A powerful and flexible relational database language composed of commands that enable users to create database and table structures, perform various types of data manipulation and data administration, and query the database to extract useful information.

What is a Database?

A shared, integrated computer structure that houses a collection of related data. A database contains two types of data: end-user data (raw facts) and metadata.

What is a Query?

A specific request issued to the DBMS for data manipulation. Example:

What is a Database System?

An organization of components that define and regulate the collection, storage, management, and use of data within a database environment.

What is Meta-Data?

Data about Data, through which the end-user data is integrated and managed.

What is the difference between Data and Information?

Data is defined as raw facts or facts that have not yet been processed to reveal their meaning to the end-user. Information is the result of processing raw data to reveal its meaning. Information consists of transformed data and facilitates decision making.

Why is Database design important?

Databases are important because it oversees and organizes the functions of an organization. It's important because it: - Keeps track of customers - what products are being sold - who is involved and working in the organization All of these are components of the organization that play into what needs to be more or less managed, along with accurately giving important information on what is being done or measured.

Why are Databases valuable assets for decision making?

Databases are valuable assets for decision-making because they inform the organization of aspects like: - Customer Tracking - What's being sold - Who is involved in the organization

What is Data Inconsistency?

Different versions of the same data appearing in different places Example: A company's sales department stores a sales representative's name as Bill Brown and the company's personnel department stores that same person's name as William G. Brown.

What are Islands of Information?

In the old file system environment, pools of independent, often duplicated, and inconsistent data created and managed by different departments. Simply Explained:

How is Information produced?

Information is produced by processing Data.

How is Information used?

Information is used to reveal the meaning of Data

What is End-User Data?

Raw facts of interest to the end user.

What is Data? (File Terminology)

Raw facts, such as a telephone number, a birth date, a customer name, and a year-to-date (YTD) sales value. Data has little meaning unless it has been organized in some logical manner.

What is Performance Tuning?

The activities that make the database perform more efficiently in terms of storage and access speed.

What is Data Type?

The kind of values that can be used or stored. Also, used in programming languages and database systems to determine the operations that can be applied to such data. Simply Explained: Example:

What are the main components of the Database system?

The main functions of DBMS are: - Hardware - Software - People - Procedures - Data

What are the main functions of a Database Management System (DBMS)?

The main functions of a DBMS are: - Making Data management more effective and efficient. - The receiving of all application requests and the translation of them into the complex operations required to fulfill those requests - The enabling of data in the database to be shared among multiple applications or users. - The integration of many different users' views of the data into a single all-encompassing data repository.

What is a Data Processing Specialist (DP)?

The person responsible for developing and managing a computerized file processing system.

What are the various types of Databases?

The various types of Databases are: - Single-User Database - Desktop Database - Multiuser Database - Workgroup Database - Enterprise Database - Centralized Database - Distributed Database - Cloud Database - General-Purpose Database - Discipline-Specific Database - Operational Database - Online Transaction Processing (OLTP) Database - Transactional Database - Production Database - Analytical Database

What is Physical Data Format?

The way a computer "sees" (stores) data. Simply Explained: How the computer must work with the data

What is Logical Data Format?

The way a person views data within the context of a problem domain. Simply Explained: How the human being views the data.

What is Data Quality?

Use or application of data and the purpose for its collection; ensuring accuracy and completeness of organization's data.

What is Data Redundancy?

What exists when the same data is stored unnecessarily at different places.

What is Data Independence?

When you can change the data storage characteristics without affecting the program's ability to access the data.

Is a Spreadsheet a Database?

While a spreadsheet allows for the manipulation of data in a tabular format, it does not support even the most basic database functionality such as support for self-documentation through metadata, enforcement of data types or domains to ensure consistency of data within a column, defined relationships among tables, or constraints to ensure consistency of data across related tables.

What is Data Integrity?

the condition in which all of the data in the database is consistent with the real-world events and conditions. Simply Explained: - If Data is accurate; then there are no data inconsistencies. - If Data is verifiable; then the data will always yield consistent results.