Big Data Yuan Xue CS 292 Special topics on

Part I Relational Database (SQL) Yuan Xue

Creating and Using a Relational Database  Steps in creating and using a (relational) database 1. Design schema (using DDL – data definition language) 2. Initialization: “Bulk load” initial data 3. Operation: execute queries and modifications (using DML – data manipulation language) Data Meta-data: database definition

SQL Introduction  Programming language for data management in a relational database management system(RDBMS)  Both Data Definition Language (DDL) and Data Manipulation Language (DML)  DDL: create, drop table  DML: query (select), insert, update and delete data from table  Standardized and supported by all major commercial database systems  One of the major reasons for commercial success of RDBMS  Interactive via GUI or command line, or embedded in programs

Data Definition in SQL

CREATE in SQL CREATE TABLE MiniTwitter.User (IDVARCHAR(20)NOT NULL, NameVARCHAR(20)NOT NULL, … PRIMARY KEY (ID) FOREIGN KEY (ID) REFERENCE Follow(Followee) FOREIGN KEY (ID) REFERENCE Follow(Follower) ); User IDName Password Aadf1234 com qwer6789 CREATE SCHEMA MiniTwitter; FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow

CREATE in SQL  Data types in SQL  Numeric  INT, FLOAT, DEC  Character, or String  CHAR, VARCHAR  Bit-string  BIT, BLOB (binary large object)  Boolean  Date, Time  DATE, TIME, TIMESTAMP CREATE TABLE MiniTwitter.Tweet (IDVARCHAR(20)NOT NULL, TimestampTIMESTAMPNOT NULL, … PRIMARY KEY (ID) ); Tweet IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure..

CREATE in SQL CREATE TABLE MiniTwitter.Follow (FolloweeVARCHAR(20)NOT NULL, FollowerVARCHAR(20)NOT NULL, TimestampTIMESTAMPNOT NULL, PRIMARY KEY (Followee, Follower) ); FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow

Data Manipulation in SQL

SELECT in SQL  SELECT-FROM-WHERE structure of basic SQL queries SELECT A 1, A 2,…,A n FROM R 1, R 2,…,R m WHERE Condition; Attribute to return Relationship/table Conditional expression

Example  Retrieve the timestamp and content of all tweets whose author is “alice00” User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

Example IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. User Tweet FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow SELECT Timestamp, Content FROM Tweet WHERE Author = ‘Alice00’; Select condition

Example  Retrieve the content of all tweets whose author is followed by “Alice00” User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

Example IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. User Tweet FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow SELECT content FROM Tweet, Follow WHERE Follower = ‘Alice00’ AND Author = Follower; Select condition Join condition Select-project-join query

Example  Retrieve the timestamp and content of all tweets whose author is followed by “Alice00” User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Qualify the attribute name to prevent ambiguity

Example IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. User Tweet FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow SELECT Tweet.Timestamp, Content FROM Tweet, Follow WHERE Follower = ‘Alice00’ AND Author = Follower; Select condition Join condition

Aggregate Functions in SQL  Aggregate function: summarize information from multiple tuples  Basic aggregate operations in SQL  COUNT, SUM, MAX, MIN, AVG  Retrieve the number of people that “Alice00” is following  Retrieve the number of people who are following “Alice00”

Aggregate Functions in SQL  Aggregate function: summarize information from multiple tuples  Basic aggregate operations in SQL  COUNT, SUM, MAX, MIN, AVG SELECT COUNT(*) FROM Follow WHERE Follower = ‘Alice00’;  Retrieve the number of people that “Alice00” is following SELECT COUNT(*) FROM Follow WHERE Followee = ‘Alice00’;  Retrieve the number of people who are following “Alice00”

Nested SQL query  Show the names of users with more than 10 followers User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

Nested SQL query User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice SELECT Name FROM User WHERE (SELECT COUNT (*) FROM Follow WHERE Followee = ID)>10);

GROUP in SQL  Show the names of all users with the number of tweets from them User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

GROUP in SQL User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice SELECT User.Name, COUNT(Tweet.ID) FROM User, Tweet WHERE User.ID = Tweet.Author GROUP BY Tweet.Author;

ORDER BY in SQL  Show the names of users who follow “Alice00” based on the time of “following” relationship User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

ORDER BY in SQL User Tweet Follow IDName Password Aadf1234 com qwer6789 IDTimestampAuthorContent Alice00Hello Bob2013Nice weather Not sure.. FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice SELECT User.Name, FROM User, Follow WHERE User.ID = Follow.Follower AND Follow.Followee = “Alice00” ORDER BY Follow.Timestamp;

INSERT in SQL INSERT INTO Follow VALUES (“Cathy123”, “Bob2013”, ) ; Follow FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Cathy123Bob Follow FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

DELETE in SQL DELETE FROM Follow WHERE Followee = ‘Alice00’ AND FOllower = ‘Bob2013’; Follow FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow FolloweeFollowerTimestamp Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

UPDATE in SQL UPDATE Follow SET Timestamp = ‘ ’ WHERE Followee = ‘Alice00’ AND Follower = ‘Bob2013’; Follow FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice Follow FolloweeFollowerTimestamp Alice00Bob Bob2013Cathy Alice00Cathy Cathy123Alice Bob2013Alice

More on SQL  Drop table  Outer Join  Indexes, Constraints, Views, Triggers, Transactions, Authorization  Substring Pattern Matching and Arithmetic Operators Check out: