Intro to Database

Question 1

Why do we need to manage data?

Answer 1

• Organizations could not function long without critical business data
• Cost to replace data would be very high
• Time to reconcile inconsistent data may be too long
• Data often needs to be accessed quickly
• Data should be:
- Cataloged
- Named in standard ways
- Protected
- Accessible to those with a need to know
- Maintained with high quality

Question 2

A collection of data that is organized in a way that facilities retrieval and reporting

Answer 2

Database

Question 3

Uses of Database

Answer 3

• Databases are commonly used to store data which are too large to be managed on a paper or through simple spreadsheets
• Most businesses use databases for accounts, inventory, personnel and other record keeping
• Databases are also becoming more widely used by home users for address books, CD collections, recipe archives, etc.

Question 4

Advantages of Database Approach

Answer 4

• Reduction in data redundancy
• Maintenance of data
• Data are self-documented or self-descriptive
• Avoidance of inconsistencies
• Reduced cost of software development
• Security restrictions

Question 5

Types of Database Software Packages

Answer 5

• File Management System

* Database Management System

Question 6

‘flat-file’

records from only one file can be related at a time

Answer 6

File Management System

Question 7

Allow records from multiple files to be related and manipulated at the same time

Answer 7

Database Management System

Question 8

Collection of interrelated data and set of programs to access the data, that provides an environment that is both convenient and efficient to use

Answer 8

Database Management System

Question 9

Database examples

Answer 9

• Customer lists
• Records related to hobbies or collections
• Employee records
• Inventories
• Sales records
• Student grades and information
• Catalogs of tapes or books

Question 10

Levels of abstraction

Answer 10

Physical level
Logical level
View level

Question 11

Describes how a record is stored

Answer 11

Physical level

Question 12

Describes data stored in database and the relationships among the data

Answer 12

Logical level

Question 13

Application programs hide details of data types; views can also hide information for security purposes

Answer 13

View level

Question 14

A way for human to visualize the relationships between records that are filed in complex database management systems

Answer 14

Data Model

Question 15

A collection of tools for describing data, data relationships, data semantics and data constraints

Answer 15

Data Model

Question 16

Types of data model

Answer 16

Hierarchical data model
Network data model
Relational data model
Object-oriented data model

Question 17

The oldest data model

Has top-down design; resembles an organizational chart or an inverted tree

Answer 17

Hierarchical data model

Question 18

Each record at one level is linked to (or has a parent at) the next level

Answer 18

Hierarchical data model

Question 19

Multiple relationships are establish between different braches of the data

Answer 19

Network data model

Question 20

The most flexible approach to database organization

Records can be related according to the contents of key fields, or common categories

Answer 20

Relational data model

Question 21

The newest data model

They link objects

Answer 21

Object-oriented data model

Question 22

Object-based logical models

Answer 22

• Entity-relationship model
• Object-oriented model
• Semantic model
• Functional model

Question 23

Record-based logical models

Answer 23

• Relational model
• Network model
• Hierarchical model

Question 24

A collection of related records that is self-describing

Answer 24

Database file

Question 25

All the information that pertains to one person, object or event

Answer 25

Record

Question 26

A required property for each field that defines the type of information that can be entered in each field The data format that a field value can hold

Answer 26

Data type

Question 27

Data types

Answer 27

``` Text Memo Number Date/Time Currency Autonumber Yes/No OLE object Hyperlink ```

Question 28

A display of records in a table

Answer 28

Datasheet

Question 29

An independent object that can be related to another in database schema; May be a person, place, thing, event, organizational grouping, etc.

Answer 29

Entity

Question 30

One category of item in a record, such as name, address or a social security number Aka column names

Answer 30

Field

Question 31

A collection of related records

Answer 31

File

Question 32

A field or attribute whose value is required to match the primary key in a table that is related to another

Answer 32

Foreign Key

Question 33

A display object that provides an easy-to-use data entry screen that generally shows only one record at a time

Answer 33

Form

Question 34

They arrange the format of a query or a report in sets of records meeting common field criteria

Answer 34

Grouping and Control Breaks

Question 35

Database model system that connects record types together so that occurrences under a given level can be used to retrieve others directly below it in a logical structure Aka tree structure

Answer 35

Hierarchical Database Model

Question 36

They are one-to-many-relationships only, which results in redundant data at the lower level of the hierarchy

Answer 36

Hierarchical records

Question 37

Special kind of field or attribute whose role is to uniquely identify a particular instance of a given identity

Answer 37

Identifiers or Key fields

Question 38

An ordered list of items coupled with an indication of where those items can be found A data structure that allows a table to be retrieved and sorted An order based upon some keys or set of fields

Answer 38

Index

Question 39

A set of format rules to aid in data entry and editing of database records, such as Zip code, Phone or Social Security Number format

Answer 39

Mask

Question 40

Command sets or program modules that are saved with a database management system; these basic code modules perform common repeatable tasks to allow operators to maintain a database system without technical knowledge of the database management system used

Answer 40

Modules

Question 41

Database model that uses pointers or links within the fields in the records to link the records together This allows many-to-one as well as one-to-many relationships, resulting in less redundancy than Hierarchical

Answer 41

Network Database Model

Question 42

Its objects possess properties and methods to be applied to data with the data itself

Answer 42

Object-oriented Database Model

Question 43

One record relates to one record in another table

Answer 43

One-to-one relationship

Question 44

An attribute or fields upon which all other fields are functionally dependent, and which is chosen as the main direct access vehicle to individual records Contents of key fields must be unique

Answer 44

Primary key

Question 45

An object which provides a table view of selective data that is a subset of fields and/or records from one or more tables

Answer 45

Query

Question 46

Mathematical, relational and logical operators that allow one to set ranges and criteria for records to be retrieved from table(s)

Answer 46

Query Operators

Question 47

A set of relational fields

Answer 47

Record

Question 48

A database model in which more than one table can share information; the tables are linked or ‘related’ with a common key field of information

Answer 48

Relational Model

Question 49

An object that creates a professional printout of data that may contain such enhancements as headers, footers and calculations on groups of records, usually based upon a query

Answer 49

Report

Question 50

A collection of records based upon some criteria or relation

Answer 50

Recordset

Question 51

A standardized data manipulation language that allows one to filter or retrieve table records by certain criteria

Answer 51

SQL (Structured/Standard Query Language)

Question 52

The physical order of the records in a table

Answer 52

Sort

Question 53

A collection of records for a single entity, such as all of the customer records

Answer 53

Table

Question 54

Means that redundant data has been scattered through the database because the designer has failed to normalize the database

Answer 54

Transitive relationships

Question 55

A dynamic datasheet or a selective recordset that allows full edit capability

Answer 55

Update query

Question 56

An internal check for values inputted into specific fields of a table

Answer 56

Validation