Test 1 Flashcards

(77 cards)

1
Q

What is a data field?

A

Information that describes a person, event or thing in a database.

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2
Q

What are other names for a data field?

A

Attribute, column or simple field

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3
Q

What is a database record?

A

Database record stores all of the information about an entity

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4
Q

What is an example of a database record?

A

One employee in a payroll file or one customer is a customer file

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5
Q

What is a database file?

A

Set of common records form a file or a table

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6
Q

What does a database file contain?

A

Contains a set of related records. e.g set of customer records or inventory records

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7
Q

What is a master file?

A

A master file is a database file that stores permanent information e.g part numbers

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8
Q

What is a transaction file

A

A transaction file is a database file that stores transient information. e.g inventory disbursement & replenishments

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9
Q

What is a database?

A

Collection of tables that contain all information needed for an accounting application. Several tables create a complete database

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10
Q

What are the two database keys

A

Primary Key & Foreign key

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11
Q

What is a primary key

A

Data field in each record that uniquely distinguishes one record from another in a database table.

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12
Q

What is the importance of a primary key?

A

It is required in every record of a database as a unique identifier

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13
Q

What is a foreign key?

A

Data fields that enable reference between records in other tables by matching the primary key of the related table

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14
Q

What is a key characteristic of a primary key

A

It must be unique

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15
Q

What is a key characteristic of a foreign key?

A

That the they match the primary key of the related table

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16
Q

What do foreign keys allow?

A

Foreign keys enable a database system to combine information from both tables to produce a report.

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17
Q

What is a data dictionary?

A

A critical component of a database document that describes the data fields in each database record

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18
Q

How do data dictionaries help with audit?

A

Establishing an audit trail as it helps to trace data paths in the new system.
Helps when investigating internal controls

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19
Q

What is the basic assumption about the REA model?

A

That business EVENTS affect firm RESOURCES and involve AGENTS

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20
Q

What is the first step to designing an REA model?

A

Identify business & economic events

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21
Q

What does REA stand for?

A

Resources, Events & Agents

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22
Q

What occurs during the Identify business & economic events stage of the REA model design?

A

Designer will try to record all events that are relevant for management decision making in the database, whether business or economic

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23
Q

What is a business event

A

An event that does not affect financial statements but can affect important aspects of the organisation. e.g hiring a new CEO

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24
Q

What is an economic event?

A

An event that typically affects an organisation financial statements. e.g sale on account

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25
What is the second step of designing an REA model?
Identify Entities
26
What are the two entities related to designing an REA model?
Internal agents | External agents
27
What are agents?
Agents are the "who" associated with events. Are either internal or external
28
What are Internal agents?
Agents that work within the firm for which the database is designed
29
What are external agents?
Agents outside of the firm. E.g a customer
30
What occurs during the second stage of designing an REA model "Identify Entities"
Identify the AGENTS and RESOURCES
31
What are resources within an REA model?
Resources represent things of economic value. - anything under the firm’s control, that provides value and of which there is limited quantity
32
What are common examples of resources within an REA model?
Cash Equipment Inventory Plant facilities
33
What is the link between events and resources?
Events use, change, transfer or generate resources
34
How does an REA model help build a database?
An REA model helps to identify database entities because each resource event & agent represents an entity in a relational database.
35
What are common examples of events
Sales Purchases Received goods Hire an employee
36
What are common examples of external agents?
Customers | Vendors
37
What are common examples of internal agents?
Employee | Manager
38
What is the 3rd step in designing an REA model?
Identify Relationships
39
What are the two types of relationships in an REA model?
Direct relationship | Indirect relationship
40
What is the importance of relationships in a database?
Relationships between entities determine the ability to create reports from data. Reports can combine data from linked entities.
41
What entities have direct relationship in an REA model?
Events typically have a direct relationship with resources agents, and other events.
42
What entities have an indirect relationship in an REA model?
Resources and Agents are indirectly linked through an event.
43
What are cardinalities?
Describe how entities are related to each other and refers to the maximum number of one entity that can occur given its relationship to another entity
44
What are the three cardinality relationships?
one-to-one one-to-many many-to-many
45
What is a common point about cardinalities regarding agents and events?
one-to-many relationship | Events involve single agents, but agents are involved in events many times.
46
What is the 4th step in designing an REA model?
Create entity relationship diagrams
47
What are entity relationship diagrams used for?
To depict entities & their relationships
48
What is the 5th step in designing an REA model?
Identify attributes of entitles
49
What occurs during the 5th step of designing an REA model "Identify attributes of entitles"
Entitles identified become tables in a database
50
How do you use the entities to create tables in a database?
Entities have characteristics or attributes that describe them & that data with a table is based on the attributes of the entity
51
What is important about attributes with an entity table in a database?
Each attribute should only describe one entity & that entity only.
52
What is the 6th step in designing an REA model?
Convert the E-R diagrams into database tables
53
What are the 5 basic rules for table creation?
- Every table has a unique name - Every row is unique - Attributes in tables have unique names - The order of the columns and rows is irrelevant - Each relation has a set of identifiers called keys
54
What is normalisation?
The methodology for ensuring that attributes are stored in the most appropriate tables & that the database promotes accurate & non redundant storage of data.
55
What is a consequence of normalisation
Can result in the creation of more tables
56
What are the steps of Normalisation?
First Normal form Second normal form Third normal form
57
When is a database in first normal form?
All non-key attributes are singular with respect to the key. Meaning that each attribute has only one value.
58
When is a database in second normal form?
When in first normal form & all attributes in each records depend entirely on the record primary key
59
When is a database in third normal form?
When in second normal form & all non-key attributes are independent. Meaning that no record contains any data fields where data field A determines data field B
60
What occurs if a database is not in normal form/
Insert anomaly Delete anomaly Update anomaly
61
What is insert anomaly?
When you want to addd a relation but cant
62
What is delete anomaly?
When you discard one item, you lose something that you still need
63
Update anomaly
Non-key data is repeated and update is difficult or impossible.
64
What is an information system?
A system is a set of two or more interrelated components that interact to achieve a goal
65
What does an information system consist of?
``` People Procedures Data Software Information technology ```
66
What are the 3 important functions of an information system?
1. It collects and stores data about activities and transactions. 2. It processes data into information that is useful for making decisions. 3. It provides adequate controls to safeguard the organization’s assets.
67
What are issues with accounting information systems?
``` Data Analytics Big Data Cyber Security Outsourcing and cloud services Hacking and malware ```
68
When creating tables, what should you do if the cardinality maximums are many-to many?
If maximums are both “many” Create new table with two key fields Add additional data if necessary
69
When creating tables, what should you do if the cardinality maximums are one-to many?
Primary key of the entity that can be linked to many instances of the other entity becomes a foreign key
70
When creating tables, what should you do if the cardinality maximums are one-to one?
Initially just add one of the key fields to the other table. Additional rules specify that you’d consider minimum cardinality
71
What is the 1st basic rule for relational databases?
Primary keys must be unique and cannot be NULL (entity integrity rule)
72
What is the 2nd basic rule for relational databases?
Foreign keys can be NULL, otherwise must have value of valid primary key being referenced (referential integrity)
73
What is the 3rd basic rule for relational databases?
Every column (other than foreign keys) must describe a fact about the primary key
74
What is important about the 3rd relational database?
every column in customer table (name, address, balance, credit limit) is a fact about customer number x; you don’t store information about products in the customer table
75
What is the 4th basic rule for relational databases?
Every column must be single-valued | cannot have a list of item numbers in a single column
76
What is the 5th basic rule for relational databases?
Data type must be constant for a column | Example: in every row, the zip code column must be a 5-digit (or 9-digit) number
77
What is the 6th basic rule for relational databases?
Neither row nor column order is significant