Lesson 18

Question 1

SQL?

Answer 1

Structured query language for writing and querying data. Used to communicate with a database. It is the standard language for relational database management systems.

Question 2

NoSQL (not only SQL)

Answer 2

Is a non-relational DMS (database management system) that doesn’t require a fixed schema, avoids joins, and easy to scale. Used for distributed stores with humongous data storage needs. Used for big data and real time web apps. Ie: twitter,fb, and Google collect terabytes of user data every single day.

Question 3

Schema

Answer 3

Logical container for database objects ( tables, views, triggers and so on) . The skeleton structure that represents the logical view of the entire database

Question 4

Primary key

Answer 4

Uniquely identifies a record in table

Question 5

Foreign key

Answer 5

Is a field in the table that is primary key in another table

Question 6

What SQL statement is used to extract data from a data base ?

Answer 6

Select

Question 7

What SQL statement is used to update data in a database?

Answer 7

Update

Question 8

What SQL statement is used to delete data from a DB?

Answer 8

Delete

Question 9

What SQL command is used to insert new data in a db?

Answer 9

Insert into

Question 10

With SQL, how do you select a column named \”firstname\” from a table named \”persons\”?

Answer 10

SELECT Firstname FROM Persons

Question 11

With SQL, how do you select all the columns from a table named \”Persons\”?

Answer 11

SELECT *FROM Persons

Question 12

What SQL command is used to return only different values?

Answer 12

SELECT DISTINCT

Question 13

What is the most common type of join?

Answer 13

INNER JOIN