1.3.2 - databases Flashcards
What is meant by the term Primary Key?(1)
It is a field with a unique value. OR A unique Identifer.(1)
What is meant by the term Foreign Key?(1)
A field that links a primary key in a second table.(1)
What is meant by Referential Integrity?(1)
Database are consistent OR Each foregin Key links to a valid Primary Key.(1)
What Does A.C.I.D stand for? (4)
Atomicity (1) Consistency(1) Isolation (1) Durability(1)
What are the 3 types of Entity Relationship?(3)
One-to-One (1) Many-to-Many (1) Many-to-One(1)
What is Flat File Database ?(1)
A single table (2) or a 2D table (1)
What is a Referential Database?(1)
Multiple tables, linked by key fields (1)
What are 4 Methods to Exchange Data (4)
CSV(1) XTML(1) JSON(1) Electronic Data Interchange (1)
Why do we use SQL?(3)
Allows fast and efficient retrieval (1) deletion(1) and manipulation of data using simple commands.
What are the 4 Methods for Capturing Data? (4)
Manual Entry (1) Optical Character Recognition {OCR}(1) Magnetic Ink Character Recognition {MICR}(1) Optical Mark Recogntion {OMR}(1)
Give an Example of Manual Entry (1)
Focal Groups (1) Verbal Surveys (1)
Give an Example of O.C.R (1)
Forms(1) Car Registration(1) Google Street-View (1)
Give an Example of M.I.C.R (1)
Bank Cheques(1) Passports (1)
Give an Example of O.M.R (1)
Multiple Choice Exams(1) Lottery Tickects (1)
Why do we use Database Manipulation Languages?(5)
Specify Tables(1) Specifiy Fields(1) Specify Criteria(1) Specify Output Sorting(1) Use Boolean Expressions(1)
Define a Record (1)
A collection of fields about the same person or item in a database(1)
Define a Field (1)
A category of information(1)
What is a Composite Primary Key? (1)
A primary Key generated by combining fields of each record to gaurantee uniqueness(1)
Compare Flat-File Databases to Relational Databases.(4)
Flat Files: Limited amount of Data(1) Limited Technical Expertise required to use Flat File databases(1) Data format difficult to change (1) Not very secure(1) Relational Database: Easy to add Data(1) Easy to link to other applications(1) Save space by reducing redundant data(1) Improves Data Consistency (1) Easy to change data Format(1) Easy to control access to data(1)
What does Atomicity mean in A.C.I.D?(1)
A transaction can be fully complete or not complete. It cannot be partially complete.(1)
What does Consistency mean in A.C.I.D?(1)
A change in the database must retain the overall state of the database.(1)
What does Isolation mean in A.C.I.D?(1)
Transaction must not interrupt one another (1)
What does Durability mean in A.C.I.D?(1)
Changes made must not be lost to system faliure.(1)
Why Normalise Databases?(2)
Reduces Redundant Data(1) Improves Data Integrity(1)
What the requirements for First Normal Form (1NF)? (3)
Field names must be unique(1)Data is Atomic (1) Has a primary key(1)
What the requriements for Second Normal Form (2NF)? (2)
It is in 1NF(1) No Partial Dependencies (1)
Define Dependency (1)
A field all other fields are dependant on.(1)
Define Partial Dependecy (1)
Field depending on parts of the primary key.(1)
What the requriements for Third Normal Form (3NF)? (2)
It is in 2NF(1) No Transitive Dependencies(1)
What is Transitive Dependency?(2)
A Non-Key Dependency (1) A value of a field is determined by the value of another field that is not the Primary Key (1)
What is a Link Table? (2)
A table used to resolve Many-to-Many relationships(1) Resolves Partial dependencies.(1)
What does * mean in SQL? (1)
SQL wildcard meaning ALL(1)
What does % mean in SQL?(1)
SQL wildcard meaning ANYTHING(1)
What is the SQL for Adding new Data to table? (1)
Insert Into (field1,field2)Values (value1,value2)(1)
What Statement in SQL deletes Data?(1)
DELETE FROM (1)
What Statement in SQL joins Two Tables togehter?(1)
JOIN ON(1)
What Statement in SQL Deletes a Table? (1)
DROP TABLE (1)
Name 2 SQL commands?(2)
SELECT(1) FROM(1) WHERE(1) LIKE(1) AND(1) OR(1) DELETE(1) INSERT(1) DROP(1) JOIN ON (1)
What is a secondary key? (2)
An indexed field (1) that allows for easier searching (1)
