writeToDB: Write The data.frame to MySQL Database

In baixueyuan/zsl: Download and manipulate discount rate of bond from China Clear.

Description

Write the data.frame to MySQL database using the method that sent the query to the database server.

Usage

writeToDB(data, channel, table, quiet = TRUE, sql.out = FALSE,
  delete.first = FALSE, primary = 1L)

writeToSQL(data, sql.file, table, append = TRUE)

Arguments

data	the data.frame will be written to the database
channel	an ODBC channel object
table	the table name of database, which is used to organized query
quiet	logical, default is TRUE, show the progress bar
sql.out	logical, whether give the SQL message, just in case there are errors occur
delete.first	logical, whether to delete the records first using the primary key column
primary	integer, which column is the primary column, and just used when delete records
sql.file	the file name of the output sql file
append	pass to the write.table function, whether overwrite the existed file or appent to it

Details

The function can delete the records before writing to the database, however if it can be make sure that the there is no duplicated records, the deletion can be skipped, saving time. The deletion work is based on the primary key, so the column index has to be given, and the column name should the same as that in the database.

The mechanism of the function is to paste an INSERT query and send to the database server. Sum method seems safe to be executed.

The function writeToSQL just save the query to the .sql file, which can be used to import to the database manually, however, this is a good choice for the big data set.

Value

Besides errors messages, no return.

baixueyuan/zsl documentation built on May 11, 2019, 5:27 p.m.