chapter 11 databases

Systems design phase

Create the new system on paper

Data

Raw facts or observations without meaning.

Information

Data that has been given context to make it useful.

Knowledge

Information combined with experience to understand how to apply it.

Wisdom

Using knowledge to make good decisions and take action.

DIKW Pyramid

A model showing how data turns into information, then knowledge, and finally wisdom.

Physical view of data

Focuses on how and where data is actually stored.

Logical view of data

Focuses on the meaning and use of data, not its physical storage.

Character

A single letter, number, or symbol.

Field

A group of characters that represents one piece of information (like a name).

Record

A complete set of related fields about one person or thing.

Table

A collection of records of the same type (like all employee records).

Database

A collection of related tables or files.

Key Field (Primary Key)

A unique identifier for each record in a table.

Data Redundancy

When the same data is stored in more than one place.

Data Inconsistency

When copies of the same data do not match.

Program

Data Dependence

Batch Processing

Collecting and processing data all at once at a later time.

Real

Time Processing

Database Management System (DBMS)

Software to create, modify, and access a database.

Hierarchical Database Model

Data organized like a family tree with one parent per child.

Network Database Model

Like a hierarchical model, but a child can have multiple parents.

Relational Database Model

Data stored in tables that can be linked together.

Multidimensional Database Model

Data organized in cubes for complex analysis.

Object

Oriented Database Model

NoSQL Database

A flexible database type for large, unstructured data, not just tables.

SQL

The standard language used to communicate with relational databases.

SELECT Operation

Picking specific rows from a table based on a condition.

JOIN Operation

Combining data from two or more tables into one view.

PROJECT Operation

Picking specific columns from a table.

Data Dictionary

A document that defines what each piece of data in a database means.

Database Administrator (DBA)

The person who manages, secures, and maintains a database.