Convenience functions for importing/exporting DBMS tables

These functions mimic their R/S-Plus counterpart get, assign, exists, remove, and objects, except that they generate code that gets remotely executed in a database engine.

Usage

# S4 method for class 'MySQLConnection,character'
dbReadTable(conn, name, row.names, check.names = TRUE, ...)

# S4 method for class 'MySQLConnection'
dbListTables(conn, ...)

# S4 method for class 'MySQLConnection,character'
dbExistsTable(conn, name, ...)

# S4 method for class 'MySQLConnection,character'
dbRemoveTable(conn, name, ...)

# S4 method for class 'MySQLConnection,character'
dbListFields(conn, name, ...)

Arguments

conn

a MySQLConnection object, produced by dbConnect

name

a character string specifying a table name.

row.names

A string or an index specifying the column in the DBMS table to use as row.names in the output data.frame. Defaults to using the row_names column if present. Set to NULL to never use row names.

check.names

If TRUE, the default, column names will be converted to valid R identifiers.

...

Unused, needed for compatiblity with generic.

Value

A data.frame in the case of dbReadTable; otherwise a logical indicating whether the operation was successful.

Note

Note that the data.frame returned by dbReadTable only has primitive data, e.g., it does not coerce character data to factors.

Examples

if (mysqlHasDefault()) {
con <- dbConnect(RMySQL::MySQL(), dbname = "test")

# By default, row names are written in a column to row_names, and
# automatically read back into the row.names()
dbWriteTable(con, "mtcars", mtcars[1:5, ], overwrite = TRUE)
dbReadTable(con, "mtcars")
dbReadTable(con, "mtcars", row.names = NULL)
}
#> Could not initialise default MySQL database. If MySQL is running
#> check that you have a ~/.my.cnf file that contains a [rs-dbi] section
#> describing how to connect to a test database.