Week 1 Flashcards by John Paul Alvarez

solve many of the problems encountered in data management

Databases

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Used in almost all modern settings involving data management:

Business
Research
Administration

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(raw facts)

Data

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(processed data with meaning)

Information

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(the body of information and facts about a specific subject)

Knowledge

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Have not yet been processed to reveal their meaning to the end user
Building blocks of information

Raw facts

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Generation, storage, and retrieval of data

Data management

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Produced by processing raw data to reveal its meaning
Requires context
Bedrock of knowledge
Should be accurate, relevant, and timely to enable good decision making

Information

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shared, integrated computer structure that stores a collection of:
End-user data: raw facts of interest to end user
Metadata: data about data
Provides description of data characteristics and relationships in data
Complements and expands value of data

Database:

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raw facts of interest to end user

End-user data:

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Metadata: data about data
Provides description of data characteristics and relationships in data
Complements and expands value of data

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data about data
Provides description of data characteristics and relationships in data
Complements and expands value of data

Metadata:

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collection of programs
Manages structure and controls access to data

Database management system (DBMS):

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Role and Advantages of the DBMS:

DBMS is the intermediary between the user and the database
DBMS enables data to be shared
DBMS integrates many users’ views of the data
Receives and translates application requests into operations required to fulfill the requests
Hides database’s internal complexity from the application programs and users

Role and Advantages of the DBMS:

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Database management system =
A Software that manage database / redundancy will be reduce /

DBMS

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Advantages of a DBMS:

Improved data sharing
Improved data security
Better data integration
Minimized data inconsistency
Improved data access
Improved decision making
Increased end-user productivity

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Databases can be classified according to:

Number of users
Database location(s)
Expected type and extent of use

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Single-user database supports only one user at a time
single-user; runs on PC

Desktop database:

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Multiuser database supports multiple users at the same time
Supports a small number of users or a specific department

Supports many users across many departments

Workgroup databases:
Enterprise database:

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Data is located at a single site

Centralized database:

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Data is distributed across different sites

Distributed database:

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Created and maintained using cloud data services that provide defined performance measures for the database

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Cloud database:

data exist in their original state

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Unstructured

data result from formatting
Structure applied based on type of processing to be performed

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Structured

data have been processed to some extent

Semistructured

represents data elements in textual format

Extensible Markup Language (XML)

Manual File Systems

Papers and pencils File cabinets Keeping books and records

Computerized File Systems Data processing (DP) specialist converted computer file structure from manual system Wrote software that managed the data Designed the application programs

Raw facts, such as telephone number, a birth date, a customer name. have less meaning unless they have ben organized in some logical terminology

Data

A character or group of character (alphabetic or numeric ) that has a specific meaning. A field is used to define and store data.

Field

A logically connected set of one or more fields that describes a person , place or thing. For example the field that constitute a record for a customer might consist of the customer name address, phone number date of birth, credit limit and unpaid balance.

Record

A collection of related record. For example a file might contain data about the students currently enrolled at Gigantic University

File

Evolution of File System Data Processing: Manual File Systems => Accomplished through a system of file folders and filing cabinets Computerized File Systems => Data processing (DP) specialist: Created a computer-based system that would track data and produce required reports File System Redux: Modern End-User Productivity Tools => Includes spreadsheet programs such as Microsoft Excel

Problems with File System Data Processing?

Lengthy development times. Difficulty of getting quick answers Complex system administration. Lack of security and limited data sharing. Extensive programming.

Structural dependence: access to a file is dependent on its own structure All file system programs must be modified to conform to a new file structure Versus Structural Independence: change file structure without affecting data access

Data dependence: data access changes when data storage characteristics change Versus Data Independence: data storage characteristics do not affect data access

We can achieve independence by differentiating between The logical data format (how human views the data) and The physical data format (how computer must work with data)

Organizational structure promotes storage of same data in different locations Islands of information: Scattered data locations

Data redundancy: same data stored unnecessarily in different places. Results in: Poor data security Data inconsistency: different and conflicting versions of same data occur at different places Data-entry errors Data integrity problems

abnormalities when all changes in redundant data are not made correctly Update anomalies Insertion anomalies Deletion anomalies

Data anomalies:

Database system consists of logically related data stored in a single logical data repository May be physically distributed among multiple storage facilities DBMS eliminates most of file system’s problems Current generation stores data structures, relationships between structures, and access paths Also defines, stores, and manages all access paths and components

due to a poorly planned design database. one exmapleof this anomaly is that repeated update each row is needed to be update takes lot of time. or we have copy of the database somewhere when we update our data but not the other copy of our database this could lead to data inconsistency. data will become unreliable and meaningless.

Updation anomaly

For example, there is a newly created college, and there is no student yet in that college but we wanted to put the college in our database. Due to a poorly designed database. Like from the example on youtube. since the there is no student we cannot put the college data because the primary key is the studentID and primary have the constraint the NOT NULL. Because of this we cannot put the data. what kind of anomaly is this.

Insertion anomaly

This anomaly happen when we lost a related data when we remove one data. For example, from the example on youtube when we delete a student due to the poorly design database college information will also be deleted. this might could to deletion anomalies because that college might not exist anymore if only one student is studying in that college.

Deletion anomaly

The Database System Environment defines and regulates the collection, storage, management, use of data

Database system:

Five major parts of a database system:

Hardware Software People Procedures Data

all the system’s physical devices

Hardware:

The Database System Environment three types of software required Operating system software DBMS software Application programs and utility software

Software:

The Database System Environment all users of the database system System and database administrators Database designers Systems analysts and programmers End users

People:

The Database System Environment instructions and rules that govern the design and use of the database system

Procedures:

DBMS Functions Most functions are transparent to end users Can only be achieved through the DBMS Functions: Data dictionary management Data storage management Data transformation and presentation Security management Multiuser access control Backup and recovery management Data integrity management Database access language and application programming interfaces Database communication interfaces

Data dictionary management Data dictionary: Stores definitions of the data elements and their relationships Data storage management Performance tuning: Ensures efficient performance of the database in terms of storage and access speed Data transformation and presentation Transforms entered data to conform to required data structures Security management Enforces user security and data privacy

Multiuser access control Sophisticated algorithms ensure that multiple users can access the database concurrently without compromising its integrity Backup and recovery management Enables recovery of the database after a failure Data integrity management Minimizes redundancy and maximizes consistency

Disadvantages of Database Systems

Increased costs Management complexity Maintaining currency Vendor dependence Frequent upgrade/replacement cycles

Week 1 Flashcards

(54 cards)