CIS chpt 3

Relational Database

(Its a model) based on the concept of two - dimensional tables. a relational database is usually designed with a number of related tables. Each of these tables contains records (listed in rows) and attributes (listed in columns). To be valuable, a relational database must be organized so that users can retrieve, ana- lyze, and understand the data they need.

Data warehouse v. data mart

A data warehouse is a repository of historical data that are organized by subject to support decision makers in the organization. Because data warehouses are so expensive, they are used primarily by large companies. A data mart is a low-cost, scaled-down version of a data warehouse that is designed for the end-user needs in a strategic business unit (SBU) or an individual department. Data marts can be implemented more quickly than data warehouses, often in less than 90 days. Further, they support local rather than central control by conferring power on the user group. Typically, groups that need a single or a few BI applications require only a data mart, rather than a data warehouse. ---Data marts are more focused

Foreign key

A foreign key is a field (or group of fields) in one table that uniquely identifies a row of another table. A foreign key is used to establish and enforce a link between two tables. We discuss foreign keys in more detail in Plug IT In 3.

Bryte

A group of 8 bits, it represents a single character. It can be a litter, number, or symbol.

Field

A logical grouping of characters into a world, A small group of words, or an identification number. Ex: A students name in the JMU system would appear in the "name" field and their JAC number would appear in a "JAC" field. Can also contain images.

Data File/Table

A logical grouping of related records

Instance of an entity

An instance of an entity refers to each row in a relational table, which is a specific, unique representation of the entity. For example, your university's student database contains an entity called STUDENT. An instance of the STUDENT entity would be a particular student. For instance, you are an instance of the STUDENT entity in your university's student database.

Data independence:

Applications and data are independent of one another; that is, applications and data are not linked to each other, so all applications are able to access the same data.

Data isolation:

Applications cannot access data associated with other applications.

Data security:

Because data are "put in one place" in databases, there is a risk of los-ing a lot of data at one time. Therefore, databases must have extremely high security measures in place to minimize mistakes and deter attacks.

DBMS

Data base management system, a set of programs that provide users with tools to create and manage a database. DBMS provide mechanisms for maintaining the integrity of stored data, managing security and user access, recovering information if the system fails, and accessing data.

Data governance

Data governance is an approach to managing information across an entire organization. It involves a formal set of business processes and policies that are designed to ensure that data are handled in a certain, well-defined fashion.

Data integrity:

Data meet certain constraints; for example, there are no alphabetic characters in a Social Security number field.

What occurs when data is no longer accurate or agreed upon?

Data rot

Data Model/ Entity

Diagram that represents entities in the database and their relationships. An entity is a person, place, thing, or event—such as a customer, an employee, or a product—about which information is maintained. Entities can typically be identified in the user's work environment. A record generally describes an entity.

Attribute

Each characteristic or quality of a particular entity is called an attribute. For example, if our entities were a customer, an employee, and a product, entity attributes would include customer name, employee number, and product color.

Primary Key

Every record in the database must contain at least one field that uniquely identifies that record so that it can be retrieved, updated, and sorted. This identifier field (or attribute) is called the primary key. For example, a student record in a U.S. university would use a unique student number as its primary key.

What is the difference between intity and entitiy

Intity are the charateristics of the entitys.

Knowledge management (KM)

Knowledge management (KM) is a process that helps organizations manipulate important knowledge that comprises part of the organization's memory, usually in an unstructured format. For an organization to be successful, knowledge, as a form of capi-tal, must exist in a format that can be exchanged among persons. In addition, it must be able to grow.

Record

Logical grouping of related filds, such as a students name, the courses taken, the date and the grade comprises a record.

Data is stored ____

On servers, they are apart of a DBMS

Bit

Smallest unit of Data a computer can process.

Data redundancy:

The same data are stored in multiple locations.

Data Hierarchy

To make data more understandable and useful they are arranged in a hierarchy. It begins and proceeds all the way to data bases. The order is: Bit, Byte, Field, Record, Data file/Table

Data inconsistency:

Various copies of the data do not agree

What is the correct order for data hierarchy?

bit. bite. field. record. file. data base.

Big Data- the three "v's"

is a collection of data so large and complex that it is difficult to manage using traditional database management systems. Because there is verity, velocity and volume. Changes quickly and there is a lot of different types. Some issues with big data are: untrusted sourced