D426 Data Management Foundations 1: Introduction to Databases

Terms and concepts from WGU course D426: Data Management and Foundations. This set is for chapter 1 of the textbook.

data

numeric, textual, visual, or audio information that describes real-world systems

scope

the amount of data produced and collected

format

how data is produced. i.e. numbers, text, image, audio, or video

access

whether a data source is private, publicly available, or a combination

analog

data encoded as continuous variations on various physical media.

Ex: audio recorded as vibrations impressed on vinyl disks

digital

data encoded as zeros and ones on electronic and magnetic media

Examples of public data sets

1. Data.gov provides more than 250,000 U.S. government data sets to support research and application development

2. Kaggle.com, owned by Google, supports an online community that allows users to find and publish data sets

3. data.nasa.gov provides numerous data sets in categories such as aerospace, earth science, and space science

4. cancer.gov/research collects and reports data and information relative to all forms of cancer

5. opendata.cityofnewyork.us contains data collected by the New York City government to support continuous monitoring and improvements to NYC and residents’ health

database

a collection of data in a structured format, ensuring that similar data is stored in a standardized manner

database management system

DBMS; software that reads and writes data in a database, ensuring that data is secure, internally consistent, and available at all times

query

a request to retrieve or change data in a database

query language

a specialized programming language, designed specifically for database systems that can read and write data efficiently and differs significantly from general-purpose languages such as Python, Java, and C++

database application

software that helps business users interact with database systems

information management system

a software application that manages corporate data for a specific business function, which usually includes a database system as well as other components, such as a user interface, business logic, and interfaces to other systems

database administrator

the person who enforces procedures for user access and database system availability

database designer

determines the format of each data element and the overall database structure. Responsibilities include:

• storage

• response time

• support for rules that govern data

database programmer

develops computer programs that utilize a database, combining query languages and general purpose languages

database user

a consumer of data in a database. Requests, updates, or uses stored data to generate reports or information. Usually accesses the database via applications but can also submit queries directly to the database.

database performance

how quickly a database responds to queries, affected by how the data is structured on storage media and how queries are processed

Requirements for large, complex databases with many users

• Performance

• authorization

• security

• rules

• recovery

database authorization

many database users should have limited access to specific tables, columns, or rows of a database, so systems control which individual users can access specific data

database security

how systems ensure users only access data they are authorized to,a s well as protecting against hackers by encrypting data and restricting access

database rules

how systems ensure that data is consistent with structural and business rules

ex. when multiple copies of data are stored in different locations, copies must be synchronized as data is updated

ex. when a course # appears in a student registration record, the course must exist in the course catalog

database recovery

how systems recoup from system failures and restore the database to a consistent state without loss of data

transaction

a group of queries that must be either completed or rejected as a whole as execution of some, but not all, of the queries results in inconsistent or incorrect data

When processing transactions, database systems must:

1. ensure transactions are processed completely or not at all

2. prevent conflicts between concurrent transactions

3. ensure transaction results are never lost

database system architecture

the internal components f a database system and the relationships between them

query processor

interprets queries, creates a plan to modify the database or retrieve data, and returns query results to the application

storage manager

translates the query processor instructions into low-level file system commands that modify or retrieve data using indexes to quickly locate data

transaction manager

ensures transactions are properly executed

log

a file containing a complete record of all inserts, updates, and deletes that the database has processed, which the transaction manager writes records to before applying changes and uses to restore the database in case of transaction or system failure

catalog/data dictionary

a directory of tables, columns, indexes, and other database objects that other components use to process and execute queries

metadata

data about the database, such as column names and the number of rows in each table, which is stored in the catalog

relational database

stores data in tables, columns, and rows, similar to a spreadsheet, with all the data in a column having the same format and all data in a row representing a single object, such as a person, place, product, or activity

SQL

“Structured Query Language;” a query language supported by all relational database systems that includes statements to read and write data, create and delete tables, and administer the database system

NoSQL

non-relational database systems optimized for big data, which became common since 2000 when the growth of the internet generated massive volumes of online data, often with poorly structured or missing information

Leading database products

1. Oracle Database

2. MySQL

3. SQL Server

4. PosgreSQL

5. MongoDB (NoSQL)