Week 1 Notes

Question 1

database and database system

Answer 1

organized collection of related information in a stored file // MS SQL Server, oracle, and access

Question 2

field or attribute

Answer 2

column

Question 3

record or tuple

Answer 3

row

Question 4

relation // entity

Answer 4

a table // group of tables

Question 5

metadata

Answer 5

data about data (table and column names, and data type included)

Question 6

domain

Answer 6

range of values within a column (can encompass entire range or be restricted i.e. restricted to decimal digits 0-9, or regional like NE/NW/MW/SE/SW)

Question 7

data validation rules

Answer 7

the enforcement of ‘uniqueness’ within data range

Question 8

Entity Relationship Diagram (ERD)

Answer 8

commonly used to design and document a database

Question 9

one- to-many relationship

Answer 9

a value that appears once as a primary key in table 1 appears (w same value) as foreign key in table 2. Denoted by infinity symbol, optional relationship

Question 10

SQL

Answer 10

3rd generational language to access info in relational databases. Allows you to insert new rows, update info in existing rows, and delete rows. Allows you to up tables with their columns, data types, and constraints. Includes many functions and procedures to manipulate and format data.

Question 11

SQL is non-procedural

Answer 11

how to access and select data is handles internally by SQL and is hidden from the user

Question 12

query

Answer 12

question or instruction to retrieve data from tables// can be done by writing SQL statement or thru various graphical aids and templates in Enterprise manager or Query analyzer

Question 13

A DBMS program can

Answer 13

access existing data, manipulate data to produce new data, generate a report, add/ update records, assign names, format, and establish relationships

Question 14

an RDBMS integrates

Answer 14

raw data/ metadata for tables, indexes, etc and instructions for forms, reports, and queries into one file

Question 15

null value indicates

Answer 15

value not assigned because it is unknown, not yet been recorded, or value for the column is not applicable
NOT A ZERO/ BLANK

Question 16

primary key

Answer 16

one or more columns in a table with unique and not null values

Question 17

data integrity

Answer 17

if two rows in a table are identical then table DOES NOT have DI

Question 18

foreign key

Answer 18

one or more columns in a table with limited/ constrained values to the primary key it references. Can be null

Question 19

the names of data types specify

Answer 19

a size (no of bits or bytes) and a structure/ arrangement to store the data.

Question 20

data types are used when

Answer 20

creating tables, when a column is added to a table, when data is retrieved from RAM or disk

Question 21

when specifying a data type

Answer 21

you are limiting the range of that data