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R and MySQL Database Tutorial

R and MySQL Database Tutorial.

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R and MySQL Database Tutorial

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  1. R and MySQL Database Tutorial

  2. # Creating a database using RMySQL in R >library(RMySQL) #Load RMySQL packagesThe function dbConnect create a connection to a DBMS.The function requires : - a character string specifying the name of DBMS driver, e.g., "RSQLite", "RMySQL", "RPostgreSQL", or an existing DBIConnection object. -authorization arguments needed by the DBMS instance; these typically include user, password, dbname, host, etc.>mydb <- dbConnect(MySQL(), user=’io’, password=’1234', host='localhost') # Connect to the local host.The function dbSendQuery only submits and synchronously executes the SQL statement to the database engine. It does not extracts any records>dbSendQuery(mydb, "CREATE DATABASE bookstore;") # Create database bookstore>dbSendQuery(mydb, "USE bookstore” ) # Use database bookstore

  3. # Creating a table in a database using RMySQL . >dbSendQuery(mydb, "drop table if exists books, authors") # Remove table if exist>dbSendQuery(mydb, " CREATE TABLE books ( book_id INT, title VARCHAR(50),author VARCHAR(50));") # creating tables in bookstore: >dbSendQuery(mydb, "ALTER TABLE books CHANGE COLUMN book_id book_id INT AUTO_INCREMENT PRIMARY KEY, CHANGE COLUMN author author_id INT,ADD COLUMN description TEXT,ADD COLUMN genre ENUM('novel','poetry','drama', 'tutorials', 'text', 'other'),ADD COLUMN publisher_id INT,ADD COLUMN pub_year VARCHAR(4),ADD COLUMN isbn VARCHAR(20);") >dbSendQuery(mydb, "CREATE TABLE authors (author_id INT AUTO_INCREMENT PRIMARY KEY, author_last VARCHAR(50), author_first VARCHAR(50),country VARCHAR(50));")

  4. # Adding data into tables # Fetch data from tables and close connection >dbSendQuery(mydb, "INSERT INTO authors (author_last, author_first, country) VALUES('Kumar','Manoj','India');") The functiondbFetchrecords from a previouslyexecutedquery. >res<-dbSendQuery(mydb, "SELECT LAST_INSERT_ID();") >last_id <-dbFetch(res) The funtiondbClearResultfreesallresources (local and remote) associated with a result set. It some cases (e.g., very large result sets) this can be a criticalstep to avoidexhaustingresources (memory, file descriptors, etc.) >dbClearResult(res) The funtiondbDisconnectcloses the connection, discardsallpending work, and freesresources (e.g., memory, sockets). >dbDisconnect (mydb)

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