Types of Data base systems and terms Flashcards
Terms
What is Datum
a single piece of information
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Term
What is Data:
facts related to any object in consideration
a collection of datum
2, 3, 5, 200, 10
Term
What is Information:
data in context and with a meaning
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Term
What is Metadata:
(also called schema)
A description of a particular piece of data, how it relates to other data, etc
ex: any organizations or data; charts, pie chart etc
What is a Database?
An organized collection of logically related data
Generally designed to allow ‘easy’ access of data
What are Object-oriented relational Databases?
supports storage of new data types
data to be stored is in the form of objects, objects to be stored in the database have attributes and methods that define what to do with the data
attributes ex: gender, age
What are Heirarcial Databases?
Looks like a tree of sorts (trunk- records, branches- fields)
Still in use in a few area
Can be highly efficient for small amount of data and very organized data
User/program must know the details of the file/record layout and did the navigation
What are Network Databases?
Supports many relationships
a complex data structure (looks like a series of rings linked together)
Still in use in a very few area
Can be highly efficient for small amount of data and very organized data
User/program must know the details of the file/record layout and did the navigation
Cheap man’s database
Looks like a file system because it is!!!
Still in use in many areas
Can be highly efficient for small amount of data and very organized data
User/program must know the details of the file/record layout and do the navigation
Example organization of music by category
Types of Databases
Relational
Data is stored in a series of interrelated tables (relations)
The primary form of databases today
Can be highly efficient for any amount of data
User/program do not know the details of the file/record layout and do no navigation
Uses Structured Query Language to access the data
Examples are: MS Access, Oracle, MySQL, MS SQL Server. DB2
In a database system what is a relationship defined as?
A description on how different tables are related
Usually tying specific columns in one table to specific columns in another
A table can have numerous relationships, or none
What is an SQL Statement?
And ‘English-like’ request to the DBMS
The smallest unit of work against the database
What is a Transaction?
A grouping of one or more SQL statements together as a single unit of work
Ensures all the work is done in one step without interruption (helps to maintain integrity)
What is a Query?
A type of SQL statement that returns selected data to the requestor
KEY POINT:
The returned data is in the form of a table
MS Access
Great for small single user applications
Poor multi-user handling
Everything stored in a single file
Tables, relationships, indexes, reports, forms, macros, etc.
Can attach to many other DBMS for data
dBase, Paradox, SQL Server, DB2, Lotus Notes, MySQL, Oracle
What are the functions of SQL?
Helps to insert, search, update and delete database records
- also helps to optimize and maintain databases and more
What does DBMS stand for?
Database Management System
What is a Database Management System (DBMS)?
Collection of programs that enables its users to access database, manipulate data and help in the representation of data
Controls access to database by various users
ex Facebook: accounts, photos, friends, personal info
ex: Service provider: Customer, plan, person info/contactinfo
a database management system helps to?
Ensure all access to info is coming from the same place
Integrity of information is reliable
Users get only the data they require
Shared access to information
What are joins in a relational database
The combining or two tables to create a unique table
Used to create reports and views
What does the SQL inner join and join command do?
Inner: Intersection (common elements)
Join: Intersection all elements
The data in a relational database is stored in a series of __________ tables
interrelated
What is a SQL LEFT JOIN?
Intersection all left elements
What is a Right join used for?
Intersection all right
What technology does Microsoft Access use?
Uses the Microsoft Jet Database Engine technology
Aka Jet Red
