DBI-wrap {pool} | R Documentation |
DBI methods (simple wrappers)
Description
These pool method for DBI generics methods check out a connection
(with poolCheckout()
), re-call the generic, then return the connection
to the pool (with poolReturn()
).
See DBI-custom for DBI methods that do not work with pool objects.
Usage
## S4 method for signature 'Pool'
dbDataType(dbObj, obj, ...)
## S4 method for signature 'Pool,ANY'
dbGetQuery(conn, statement, ...)
## S4 method for signature 'Pool,ANY'
dbExecute(conn, statement, ...)
## S4 method for signature 'Pool,ANY'
dbListFields(conn, name, ...)
## S4 method for signature 'Pool'
dbListTables(conn, ...)
## S4 method for signature 'Pool'
dbListObjects(conn, prefix = NULL, ...)
## S4 method for signature 'Pool,ANY'
dbReadTable(conn, name, ...)
## S4 method for signature 'Pool,ANY'
dbWriteTable(conn, name, value, ...)
## S4 method for signature 'Pool'
dbCreateTable(conn, name, fields, ..., row.names = NULL, temporary = FALSE)
## S4 method for signature 'Pool'
dbAppendTable(conn, name, value, ..., row.names = NULL)
## S4 method for signature 'Pool,ANY'
dbExistsTable(conn, name, ...)
## S4 method for signature 'Pool,ANY'
dbRemoveTable(conn, name, ...)
## S4 method for signature 'Pool'
dbIsReadOnly(dbObj, ...)
## S4 method for signature 'Pool'
sqlData(con, value, row.names = NA, ...)
## S4 method for signature 'Pool'
sqlCreateTable(con, table, fields, row.names = NA, temporary = FALSE, ...)
## S4 method for signature 'Pool'
sqlAppendTable(con, table, values, row.names = NA, ...)
## S4 method for signature 'Pool'
sqlInterpolate(conn, sql, ..., .dots = list())
## S4 method for signature 'Pool'
sqlParseVariables(conn, sql, ...)
## S4 method for signature 'Pool,ANY'
dbQuoteIdentifier(conn, x, ...)
## S4 method for signature 'Pool'
dbUnquoteIdentifier(conn, x, ...)
## S4 method for signature 'Pool'
dbQuoteLiteral(conn, x, ...)
## S4 method for signature 'Pool,ANY'
dbQuoteString(conn, x, ...)
## S4 method for signature 'Pool'
dbAppendTableArrow(conn, name, value, ...)
## S4 method for signature 'Pool'
dbCreateTableArrow(conn, name, value, ..., temporary = FALSE)
## S4 method for signature 'Pool'
dbGetQueryArrow(conn, statement, ...)
## S4 method for signature 'Pool'
dbReadTableArrow(conn, name, ...)
## S4 method for signature 'Pool'
dbSendQueryArrow(conn, statement, ...)
## S4 method for signature 'Pool'
dbWriteTableArrow(conn, name, value, ...)
Arguments
dbObj |
A DBI Driver][DBI::DBIDriver-class] or DBI Connection. |
obj |
An R object whose SQL type we want to determine. |
... |
Other arguments passed on to methods. |
conn |
|
statement |
a character string containing SQL. |
name |
The table name, passed on to
|
prefix |
A fully qualified path in the database's namespace, or |
value |
A data.frame (or coercible to data.frame). |
fields |
Either a character vector or a data frame. A named character vector: Names are column names, values are types.
Names are escaped with A data frame: field types are generated using
|
row.names |
Must be |
temporary |
If |
con |
A database connection. |
table |
The table name, passed on to
|
values |
A data frame. Factors will be converted to character vectors.
Character vectors will be escaped with |
sql |
A SQL string containing variables to interpolate.
Variables must start with a question mark and can be any valid R
identifier, i.e. it must start with a letter or |
.dots |
A list of named arguments to interpolate. |
x |
A character vector, SQL or Id object to quote as identifier. |
Examples
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())
# 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)