Database Management Ch. 2

Front 1

repeating groups

Back 1

multiple entries

Front 2

relational database

Back 2

collection of relations

Front 3

qualify

Back 3

combining a column name with a table name, i.e. Rep.RepNum

Front 4

primary key

Back 4

column or collection of columns that uniquely identifies a given row in the table

Front 5

query

Back 5

question represented in a way that the DBMS can recognize

Front 6

Query by Example

Back 6

QBE - approach to writing queries that is visual - using onscreen grids and controls

Front 7

design grid

Back 7

area where you specify the format of your output

Front 8

criteria

Back 8

conditions that data must satisfy

Front 9

comparison operator/relational operator

Back 9

>,<,=

Front 10

compound criteria/compound conditions

Back 10

multiple comparisons used to select values

Front 11

computed field

Back 11

field that is the result of a calculation

Front 12

aggregate functions

Back 12

count, sum avg, max, min etc.

Front 13

grouping

Back 13

creating groups of records that share some common characteristics

Front 14

sort key

Back 14

field on which the records or sorted

Front 15

major sort key

Back 15

first sort key in a series of keys (farthest left)

Front 16

minor/secondary sort key

Back 16

less important sort - sorted after primary

Front 17

join line

Back 17

line that indicates how tables are related

Front 18

update query

Back 18

makes a change to all records that satisfy the given criteria

Front 19

Delete query

Back 19

deletes all the records satisfying the criteria entered

Front 20

make-table query

Back 20

creates a new table using the query results

Front 21

relational algebra

Back 21

theoretical way of manipulating a relational database - operations that work on multiple tables

Front 22

SELECT command

Back 22

retrieves certain rows from a table

Front 23

SELECT Customer WHERE CustomerNum=282
GIVING Answer

Back 23

(creates a new table called answer from the row where customer number is 282)

Front 24

PROJECT

Back 24

Takes a vertical subset (columns) of a table

Uses OVER

Front 25

PROJECT Customer OVER (CustomerNum, CustomerName)
GIVING Answer

Back 25

Creates a table named answer that contains Customer Number & Name columns

Front 26

JOIN command

Back 26

command that joins tables based on matching values

Front 27

JOIN Customer Rep
WHERE Customer.RepNum=Rep.RepNum
GIVING temp

PROJECT Temp OVER (CustomerNum, CustomerName, RepNum)
GIVING Answer

Back 27

Joins Customer and Rep using the RepNum attribute and takes customer number name and repnumber columns and puts them in a new table

Front 28

outer Join

Back 28

unmatched records are included and the values of the fields are null for records that do not have commonalities

Front 29

Union

Back 29

Contains all rows in either A or B and all rows in both

Front 30

Intersection

Back 30

Contains all rows common to both A and B

Front 31

difference

Back 31

Set of all rows that are in A but not B

Front 32

Union Compatable

Back 32

Same number of Columns and they represent the same data

Front 33

UNION Tbl1 WITH Tbl2 GIVING Answer

Back 33

Creates table answer from the UNION of Tbl 1 and 2

Front 34

INTERSECT Tbl1 WITH tbl2 GIVING Answer

Back 34

Creates table Answer from the intersection of 1 and 2

Front 35

SUBTRACT Tbl1 FROM Tbl2 GIVING Answer

Back 35

Difference between 2 tables

Front 36

PRODUCT

Back 36

concatenating every row in table 1 with every row in table 2