Database Systems

Question 1

Data functions

Answer 1

Output the current date or time and are used either to filter records or to write date and time information

• CURRENT_DATE
• CURRENT_TIMESTAMP

Question 2

String functions

Answer 2

CONCAT(..,..) - combines the values passed as parameters to a character string
CONCAT_WS(separator,…,…) - combines the values passed as parameters to a character string. Always insert the characters passed as the first parameter as a separator between 2 values

Question 3

ORDER BY + sequence indicators

Answer 3

ORDER BY is used to sort the result set of a query
DESC=descending
ASC=ascending
-(NS) = default value = ascending

Question 4

Keywords for calculations

Answer 4

COUNT
SUM
AVG
MAX
MIN

Question 5

Column comparitive operator

Answer 5

ANY
ALL
EXISTS

Question 6

Types of N:M Relationships

Answer 6

N:M
N:CM
CN:CM

Question 7

Types of 1:1 relationships

Answer 7

1:1
1:C
C:C

Question 8

Types of 1:N relationships

Answer 8

1:N
1:CN
C:CN
C:N

Question 9

SQL command to create a table

Answer 9

CREATE TABLE name(
column defintion
primary key definition
[integrity rules, background]
[foreign key definition]
[specifying conditions for columns]
)

Question 10

Column defintion

Answer 10

General schema for defining columns can be specified as follows:
name data type [NOT NULL] [DEFAULT default value] [UNIQUE] [CHECK (condition)]