Databases and Distributed Systems Flashcards
1
Q
Acceptance Testing
A
will be carried out by the customer. They will test that a system meets their requirements. If the system passes this test the customer will sign-off the system as being ready for deployment into production running
2
Q
ACID Properties
A
atomicity, consistency, isolation, durability
ensure database operations execute properly without errors
3
Q
Attribute
A
a feature of an entity
4
Q
Automated Testing
A
where computer-controlled equipment tests programs for functionality and performance
5
Q
Automatic Formatting of Code
A
automatically formats code in the right way, for example, automatically indenting code
6
Q
Big Data
A
data too large to process via traditional means, with main characteristics being volume, velocity and variability
7
Q
Binary File
A
stores data in non-human readable format
8
Q
Bill Inmon
A
father of the data warehouse
9
Q
Black-Box Testing
A
a test technique in which the test feeds specific pieces of data into a system, before looking for expected outcome
10
Q
Branch
A
requests and independent line of development that stems from a central database
11
Q
Break Points
A
causes the program to run up to a point and then pause, allowing for variable inspection
12
Q
Business Modelling
A
proposed plans can use past data to model outcomes
13
Q
Check In
A
involves uploading a modified file after making changes locally
14
Q
Check Out
A
refers to process by which a developer or user acquires a copy of a specific version of a file
15
Q
Code Repository
A
these hold libraries of reusable code or data
16
Q
Commodity Clustering
A
the process of constructing a ‘cluster’ from a set of processing nodes integrated via one or more interconnection networks and secondary storage, giving the illusion of a single computer
17
Q
Composite Key
A
set of two or more fields that together uniquely identify each record in a table
18
Q
Conceptual Model
A
a representation of the data requirements of an organisation constructed in a way that is independent of any software that is used to construct the database
19
Q
Concurrency
A
a unique characteristic enabling two or more users to retrieve information from the database at the same time without affecting database integrity
20
Q
CASE
A
Computer-Aided Software Engineering
the name given to a range of software tools that aid the design, development and testing of different types of software
21
Q
Lower CASE
A
provides support in the later stages such as testing
22
Q
Upper CASE
A
provide support for the early stages of the system’s development life cycle, providing support for stages such as design
23
Q
Data
A
a set of raw facts and figures with no apparent meaning
24
Q
Database
A
a structure collection of data
25
Database Administrators
specially trained people to install and manage databases
26
Database Management System (DBMS)
a software system that enables the definition, creation and maintenance of a database and which provides controlled access to the database
27
Data Dictionary
a collection of data and attributes about data elements that are being used in a database, describing the meanings and purpose of data elements within the projects context and provides guidance on interpretation
28
Database Integrity
how accurate a database is, questioned in flatfile databases, because if one entity changes, multiple records have to be changed
29
Database Method
because all access to the database is under DBMS, all data is under centralised control, so the system is program-data independent, making it easier to control access to data, backup data and access data and create new applications
30
Database Normalisation
a database design tool used to optimise database design by turning flat-file databases into relational databases and optimising their design
31
First Normal Form
where each entity has a primary key value and no repeating groups of data
32
Second Normal Form
based on full-functional dependencies, where entities are already in first normal form and all attributes are dependent on the primary key
33
Third Normal Form
entities must be in second form with no transitive dependencies removed meaning non-key items must not depend on other non-key items
34
Database Schema
a definition of the database in a formal language that is used by the DBA
35
Conceptual Schema
the overall database structure
36
Logical Schema
tables, fields and relationships
37
Physical Schema
every part of the database including files and storage details, contains the whole database
38
Sub-Schemas
contains a subsection of the physical schema, holding the entities that a particular user needs to have access to
39
Database Triggers
modules of code stored in the data dictionary that runs when associated events occur
40
Data Constraints
describe rules which apply to data
41
Data Mart
are often smaller than data warehouses with fewer data sources and do not have as long life space; they are often project focused with limited use and are often terminated once a project is finished
42
Data Mining
the process of searching and analysing a large batch of raw data in order to identify patterns and extract useful information
43
Data Model
a method of describing the data, its structure, its relationships and its constraints that apply to the data for a given system or organisation
44
Data Redundancy
where data is unintentionally duplicated, reduced in databases
45
Data Requirements
states which data needs to be stored
46
Data Warehouse
47
DBMS Layer
acts as a layer of software between all the users and the database
48
DDL
Data Description Language
used to control the structure of the database, to creawte new entities, attributes, keys and relationships, and give access rights to users
49
Degree of Relationship
between two entities, refers to the number of entity occurrences of one entity which are associated with just one entity occurrence of the other and vice versa
50
Deletion Anomalies
occur when information is lost because a single record is removed from the fact-file
51
Distributed Processing
involves distributing and processing big data across multiple nodes through parallel processing, therefore making data processing and analysis significantly faster and more efficient
52
DML
Data Manipulation Language
controls data within the database, carrying out four basic functions: appending, deleting, amending and retrieval
53
Entity
the thing you are collecting data about
54
Entity Relationship Diagram (ERD)
shows how different entities relate to each other in an application or database
55
Field
a single piece of information which is stored within a row, for example, first name, email, date of birth
56
File
a data structure that is always stored on a device that is a collection of records
57
Flatfile Database
one spreadsheet with one table, eg Excel
58
Foreign Key
a field in one table that is a primary key in another table and is used to create a link between these tables
59
Fully Functional Backup
occurs in second normal form where all entities must be in first normal form and all partial key dependencies
60
Hierarchical Database
a data model where the database is arranged into a parent-child structure
61
Horizontal Scaling
the process of adding more machines or nodes to a resource pool in a system to distribute the workload
62
Information
data with meaning
63
Inheritance
the relationship between two object types in which one is a kind of the other and shares some of its properties or behaviours
64
Integrated Data
where data is collected from a range of sources, transformed into common format, then loaded into the warehouse, integrating data into a single source
65
Locking
where the DBMS places a lock on the record, giving read/write access rights to the first user who opens the record, and read-only rights to any subsequent user, meaning it is locked until the first user has finished editing it and commits their changes to the database
66
Logical Model
specifies the entities we are storing data on: their attributes and the degree of the relationships between the entities
67
Manual Testing
where a person manually tests programs for functionality and performance
68
Memory Protection
a way to control memory access rights to a computer, where RAM is set up so that, by default, it cannot access various pieces of data without causing a memory error so that two programs cannot use the same memory location
69
Merging
joining data from multiple sources
70
Multi-Transactions
consists of multiple, interdependent transactions spread across different databases and systems, eg transferring money from one account to another
71
Network Database
represents data in a tree-like structure, where pointers connect records in a network or graph structure
72
Normalised Entity
a set of entities that contain no redundant data
73
ODBC
Open Database Connectivity
a protocol applied to databases allowing a database made using one piece of database software to be viewed using another piece of database software, using an open standard Application Program Interface so the database can be used in another application
74
OODB
Object-Oriented Database
the same concepts applied to Object-Oriented Languages can be applied to databases, so data is stored within objects along with the methods and processes that will be carried out on the data
75
OS Authentication
where authentication is delegated to the OS
76
Performance Testing
carried out to ensure that a system will be able to cope with the required workload
77
Physical Model
adds detail to allow the data model to be implemented with a specific DBMS
78
Primary Key
a single field that acts as a unique identifier for each record in a table
79
Program-Data Independence
where changes to the program design don’t force the data file structure to be changed
80
Record
a collection of data for one item, person or thing
81
Referential Integrity
if a value appears in a foreign key in one table it must also appear in the primary key in another table
82
Relation
set of attributes and tuples, modelling an entity
83
Relational Database
a database where data is held in more than one table, with tables linked together using relationships
84
Relationship
a link between two entities, implemented in a database using primary and foreign keys
85
Resource-Related Failures
where the program runs out of memory or requires external files that are missing or inaccessible
86
Roll-Back
allows software developers to undo changes made to a system and revert back to a previous version
87
Run-Time Diagnostics
this creates a virtual machine that emulates a system that the program is designed for when it’s not specifically designed for that platform
88
Schemas
a collection of database objects
89
Screen Design Software
allows the design of screens
90
Secondary Key
any index that is not the primary key
91
Shared Memory
where memory protection does not occur but may lead to memory corruption if it is not made read-only
92
Single Transaction
refers to a series of one or more database operations resulting in one action, completed successfully, such as withdrawing money from an ATM
93
Software Engineering
an engineering approach to software development and is the process of designing, developing, testing, and maintaining software systems, different to programming due to the focus on engineering, so a software engineer will involve more mathematic and scientific methods
94
Step Through
steps through program one statement at a time, allowing faults in program logic to be identified
95
Strategic Planning
a use for data warehousing, involves knowing past sales patterns, in order to plan ahead eg buying in stock, advertising campaigns and promotions
96
Subject Oriented
when a data warehouse is used to analyse a particular subject area
97
Syntax Highlighting
displays code in different colours and fonts according to categories of terms
98
System Testing
often carried out by a specialist testing team, who will check that the system as a whole works as required. System testers will not usually be involved in the development of individual programs
99
Table
collection of related data made up of fields and records
100
Tagging Version
allows developers to assign a label to a specific point in history, serving as a reference point
101
Text File
shares data in human readable format
102
Transaction
this represents a change in the database, providing reliable units of work to allow database recovery and provide isolation between programs accessing a database concurrently
103
Transitive Dependencies
means there must be no unique associations between attributes in the record that are not used as a primary key
104
Unit Testing
often performed by the developer, and check that a program functions as required
105
Unproductive Maintenance
where changes to program design force the data file structure to be changed, occurs in factfiles
106
Update Anomaly
occurs in flatfiles where records are not correctly updated causing data corruption and reducing data integrity
107
Variable Watch
the act of observing a specific variable whilst the program runs, which the programmer can do whilst using variable inspection
108
Version Numbers
where previous versions are numbered in order to keep track of the current version
109
Vertical Scaling
the process of increasing power to individual machines in the system
110
Warning Messages
allow early detection of issues such as unused variables optimising performance
111
Whitebox Testing
tester will feed data into a system that ensure that all path through the code are used and therefore testing
112
Wire-Framing Software
help map out the user experience, layout, and overall flow, streamlining the design process
