R: DBIConnection methods.

DBI-connection {pool} | R Documentation

## DBIConnection methods.

### Description

Pool object wrappers around DBIConnection methods. For the original documentation, see:

- `dbSendQuery`

- `dbGetQuery`

- `dbExecute`

- `dbListResults`

- `dbListFields`

- `dbListTables`

- `dbReadTable`

- `dbWriteTable`

- `dbExistsTable`

- `dbRemoveTable`

### Usage

    ## 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, ...)

### Arguments

`conn, statement, ...` | See `dbSendQuery`.
`name, value` | See `dbWriteTable`.

### Examples

    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")
    }

[Package pool version 0.1.4.1 Index]