SQL
What year was SQL created?
1974
What are the basic commands in SQL?
Create, Select, Insert, Update, Drop, Delete
What is RDBMS and what are some examples?
RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. The data in RDBMS is stored in database objects called tables. A table is a collection of related data entries and it consists of columns and rows.
Who is the father of relational databases and why?
In 1970, Dr. Edgar F. "Ted" Codd of IBM described a relational model for databases.
What does an SQL engine query handle?
SQL engine is defined as software that recognizes and interprets SQL commands to access a relational database and interrogate data. SQL engine is also commonly referred to as a SQL database engine or a SQL query engine.
Predicate
conditions
How do you get a count of the number of rows
SELECT COUNT (*) FROM
Command used to get a unique values from a column (won't get duplicate values)
SELECT DISTINCT
How to alias so columns will have different names
SELECT MAX(budget) AS max_budget, MAX(duration) AS max_duration FROM films;
Describe the BETWEEN command
SELECT ___(___) FROM ___ WHERE ___ BETWEEN ___ AND ___;
Choose words that start with B or the second letter is r and doesn't start with A
SELECT name FROM PEOPLE WHERE name LIKE 'B%' OR name LIKE '_r%' AND name NOT LIKE 'A%'
How to get the average, sum, maximum, or minimum?
SELECT AVG() SELECT SUM() SELECT MAX() SELECT MIN()
Comparison operators
= equal <> not equal < less than > greater than <= less than or equal to >= greater than or equal to
What does a classic query engine handle?
A classic query engine handles all the non-SQL queries
DDL (Data Definition Language)
A part of SQL that is used to create and modify objects of a database such as tables, views, functions and stored procedures
Describe the AND and OR and IN commands
AND and OR are logical operators and IN allows you to specify multiple values in a WHERE clause and is good can be used instead of multiple OR operators.
Data Manipulation Language (DML)
DBMS language that changes database content, including data element creations, updates, insertions, and deletions. Create, read, update, or delete records (CRUD)
What does SQL stand for? What is it used for?
Structured Query Language. It's a computer language for storing, manipulating and retrieving data stored in a relational database.
What clause allows you to filter based on both text and numeric values in a table.
WHERE. WHERE always comes after FROM ex. SELECT title FROM films WHERE title = 'Metropolis';
Expression
Represents value
What is a query dispatcher?
The function of the dispatcher is to route the query request to either CQE or SQE, depending on the attributes of the query. All queries are processed by the dispatcher. It cannot be bypassed.
