| DBI-connection {pool} | R Documentation |
Pool object wrappers around DBIConnection methods. For the original documentation, see:
## S4 method for signature 'Pool' dbSendQuery(conn, statement, ...) ## S4 method for signature 'Pool,character' dbGetQuery(conn, statement, ...) ## S4 method for signature 'Pool,character' dbExecute(conn, statement, ...) ## S4 method for signature 'Pool' dbListResults(conn, ...) ## S4 method for signature 'Pool,character' dbListFields(conn, name, ...) ## S4 method for signature 'Pool' dbListTables(conn, ...) ## S4 method for signature 'Pool,character' dbReadTable(conn, name, ...) ## S4 method for signature 'Pool,ANY' dbWriteTable(conn, name, value, ...) ## S4 method for signature 'Pool,ANY' dbExistsTable(conn, name, ...) ## S4 method for signature 'Pool,ANY' dbRemoveTable(conn, name, ...)
conn, statement, ... |
See |
name, value |
See |
if (requireNamespace("RSQLite", quietly = TRUE)) {
mtcars1 <- mtcars[ c(1:16), ] # first half of the mtcars dataset
mtcars2 <- mtcars[-c(1:16), ] # second half of the mtcars dataset
pool <- dbPool(RSQLite::SQLite(), dbname = ":memory:")
# write the mtcars1 table into the database
dbWriteTable(pool, "mtcars", mtcars1, row.names = TRUE)
# list the current tables in the database
dbListTables(pool)
# read the "mtcars" table from the database (only 16 rows)
dbReadTable(pool, "mtcars")
# append mtcars2 to the "mtcars" table already in the database
dbWriteTable(pool, "mtcars", mtcars2, row.names = TRUE, append = TRUE)
# read the "mtcars" table from the database (all 32 rows)
dbReadTable(pool, "mtcars")
# get the names of the columns in the databases's table
dbListFields(pool, "mtcars")
# use dbExecute to change the "mpg" and "cyl" values of the 1st row
dbExecute(pool,
paste(
"UPDATE mtcars",
"SET mpg = '22.0', cyl = '10'",
"WHERE row_names = 'Mazda RX4'"
)
)
# read the 1st row of "mtcars" table to confirm the previous change
dbGetQuery(pool, "SELECT * FROM mtcars WHERE row_names = 'Mazda RX4'")
# drop the "mtcars" table from the database
dbRemoveTable(pool, "mtcars")
# list the current tables in the database
dbListTables(pool)
poolClose(pool)
} else {
message("Please install the 'RSQLite' package to run this example")
}