MySQLDriver-class: Class MySQLDriver with constructor MySQL.

Description Usage Arguments Examples

Description

An MySQL driver implementing the R database (DBI) API. This class should always be initialized with the MySQL() function. It returns a singleton that allows you to connect to MySQL.

Usage

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MySQL(max.con = 16, fetch.default.rec = 500)

Arguments

max.con

maximum number of connections that can be open at one time. There's no intrinic limit, since strictly speaking this limit applies to MySQL servers, but clients can have (at least in theory) more than this. Typically there are at most a handful of open connections, thus the internal RMySQL code uses a very simple linear search algorithm to manage its connection table.

fetch.default.rec

number of records to fetch at one time from the database. (The fetch method uses this number as a default.)

Examples

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if (mysqlHasDefault()) {
# connect to a database and load some data
con <- dbConnect(RMySQL::MySQL(), dbname = "test")
dbWriteTable(con, "USArrests", datasets::USArrests, overwrite = TRUE)

# query
rs <- dbSendQuery(con, "SELECT * FROM USArrests")
d1 <- dbFetch(rs, n = 10)      # extract data in chunks of 10 rows
dbHasCompleted(rs)
d2 <- dbFetch(rs, n = -1)      # extract all remaining data
dbHasCompleted(rs)
dbClearResult(rs)
dbListTables(con)

# clean up
dbRemoveTable(con, "USArrests")
dbDisconnect(con)
}

RMySQL documentation built on May 29, 2017, 7 p.m.

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