How to load table from SQL server using H2o in R?

问题

I try to load table into R using h2o but had the following error

my_data <- h2o.import_sql_table(my_sql_conn, table, username, password)

ERROR: Unexpected HTTP Status code: 500 Server Error (url = http://localhost:54321/99/ImportSQLTable)

java.lang.RuntimeException [1] "java.lang.RuntimeException: SQLException: No suitable driver found for jdbc:mysql://10.140.20.29/MySQL?&useSSL=false\nFailed to connect and read from SQL database with connection_url: jdbc:mysql://10.140.20.29/MySQL?&useSSL=false"

Can someone help me with this? Thank you so much!

回答1:

You need a supported JDBC (Build on JDBC 42 Core) driver to connect from H2O to SQL Server. You can download Microsoft JDBC Driver 4.2 for SQL Server from the link below first:

https://www.microsoft.com/en-us/download/details.aspx?id=54671

After that please follow the article below to first test JDBC driver from R/Python H2O client and then connect to your database:

https://aichamp.wordpress.com/2017/03/20/building-h2o-glm-model-using-postgresql-database-and-jdbc-driver/

Above article is for postgres however you can use it with SQL server using an appropriate driver.

回答2:

For Windows, remember to use ; instead : for the -cp argument.

java -Xmx4g -cp sqljdbc42.jar;h2o.jar water.H2OApp -port 3333

water.H2OApp is the main class in h2o.jar.

Important Note: SQL Server is not supported so far( August/2017). You may use MariaDB to load datasets:

From Windows console:

java -Xmx4G -cp mariadb-java-client-2.1.0.jar;h2o.jar water.H2OApp -port 3333

Note. For Linux, replace ";" with ":"

From R:

sqlConn <- "jdbc:mariadb://10.106.7.46:3306/DBName"
userName <- "dbuser"
userPass <- "dbpass."
sql_Query <- "SELECT * FROM dbname.tablename;"
mydata <- h2o.import_sql_select( sqlConn, sql_Query, userName, userPass )

来源：https://stackoverflow.com/questions/43851748/how-to-load-table-from-sql-server-using-h2o-in-r

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h2o