我正在尝试将 R + MonetDB 用作大数据分析堆栈,但在创建新列并用我的分析中的数据填充它时遇到了麻烦。这是一个玩具示例:
library(MonetDBLite)
library(DBI)
data(mtcars)
db <- dbConnect(MonetDB.R::MonetDB(), embedded="./test.db")
# load mtcars into the database
dbWriteTable(conn=db, value = mtcars, name = "mtcars", overwrite=TRUE)
## Add a new column
dbSendQuery(db, "ALTER TABLE mtcars ADD v1 DOUBLE;")
## insert data into the new column
v1 <- mtcars["mpg"] * pi
dbSendQuery(db, "INSERT INTO mtcars (v1) VALUES (?)", bind.data=v1)
和错误信息:
Error in .local(conn, statement, ...) :
Unable to execute statement 'INSERT INTO mtcars (v1) VALUES ('c(65.9734457253857, 65.9734457253857, 71.6283125018473, 67.23008278...'.
Server says 'ERROR: 49.6371639267187, 61.8893752757189, 47.1238898038469, 67.2300827868216)' to type dbl failed.
' [#conversion of string 'c(65.9734457253857, 65.9734457253857, 71.6283125018473, 67.2300827868216, 58.7477826221291, 56.8628270299753, 44.924774946334, 76.6548607475909, 71.6283125018473, 60.318578948924, 55.9203492338983, 51.5221195188726, 54.3495529071034, 47.7522083345649, 32.6725635973338, 32.6725635973338, 46.18141200777, 101.787601976309, 95.5044166691297, 106.499990956694, 67.5442420521806, 48.6946861306418, 47.7522083345649, 41.7831822927443, 60.318578948924, 85.7654794430014, 81.6814089933346, 95.5044166691297,
].
In addition: Warning message:
In if (is.na(value)) statement <- sub("?", "NULL", statement, fixed = TRUE) else if (valueClass %in% :
the condition has length > 1 and only the first element will be used
从这个错误我推测可能bind.data
不能与MonetDBLite
?
问题:
如何将列添加到 MonetDBLite 表并使用 R 会话中的数据填充它?