$1.$ Create a schema employee

$2.$ Write a SQL statement to create a simple table countries including columns

country$\_$id$,$country$\_$name and region$\_$id$.$

$3.$ Write a SQL statement to create a table named jobs including columns

job$\_$id$,$ job$\_$title, min$\_$salary, max$\_$salary and check whether the max$\_$salary

amount exceeding the upper limit $25000.$

$4.$ Write a SQL statement to create a table job$\_$history including columns

employee$\_$id$,$ start$\_$date, end$\_$date, job$\_$id and department$\_$id and make sure

that, the employee$\_$id column does not contain any duplicate value at the time

of insertion and the foreign key column job$\_$id contain only those values which

are exists in the jobs table.

Here is the structure of the table jobs;

$+------------+--------------+------+-----+---------+-------+$

$|$ Field $|$ Type $|$ Null $|$ Key $|$ Default $|$ Extra $|$

$+------------+--------------+------+-----+---------+-------+$

$|$ JOB$\_$ID $|$ varchar$(10)|$ NO $|$ PRI $|||$

$|$ JOB$\_$TITLE $|$ varchar$(35)|$ NO $||$ NULL $||$

$|$ MIN$\_$SALARY $|$ decimal$(6,0)|$ YES $||$ NULL $||$

$|$ MAX$\_$SALARY $|$ decimal$(6,0)|$ YES $||$ NULL $||$

$+------------+--------------+------+-----+---------+-------+$

$5.$ Write a SQL statement to create a table departments

$|$ Field $|$ Type $|$ Null $|$ Key $|$ Default $|$ Extra $|$

$+-----------------+--------------+------+-----+---------+-------+$

$|$ DEPARTMENT$\_$ID $|$ decimal$(4,0)|$ NO $|$ PRI $|0||$

$|$ DEPARTMENT$\_$NAME $|$ varchar$(30)|$ NO $||$ NULL $||$

$|$ MANAGER$\_$ID $|$ decimal$(6,0)|$ NO $|$ PRI $|0||$

$|$ LOCATION$\_$ID $|$ decimal$(4,0)|$ YES $||$ NULL $||$

$+-----------------+--------------+------+-----+---------+-------+$

$6.$ Write a SQL statement to create a table employees including columns

employee$\_$id$,$ first$\_$name, last$\_$name, email, phone$\_$number hire$\_$date, job$\_$id$,$

salary, commission, manager$\_$id and department$\_$id and make sure that, the

employee$\_$id column does not contain any duplicate value

at the time of insertion and the foreign key columns combined by

department$\_$id and manager$\_$id columns contain only those unique

combination values, which combinations are exists in the departments

table.