Maybe a simple dbWriteTable( db, "frames", iris )
does what you want? On Monday 15 July 2013 23:43:18 Simon Zehnder wrote: > Dear R-Users, > > I need a very fast and reliable database solution so I try to serialize a > data.frame (to binary data) and to store this data to an SQLite database. > > This is what I tried to do: > > library(RSQLite) > con <- dbDriver("SQLite") > db <- dbConnect(con, "test") > dbSendQuery(db, 'CREATE TABLE frames("simID" INT, "data" BLOB)') > data.bin <- serialize(iris, NULL, ascii = FALSE) > dbSendQuery(db, paste("INSERT INTO frames VALUES(1, X'", data.bin, "')", sep > = "")) > data.bin2 <- dbGetQuery(db, "SELECT DATA FROM frames WHERE simID = 1") > data.bin2 > data > 1 58 > > So, only the first entry of data.bin is saved to the database. I tried to > first convert the binary data to raw data: > data.raw <- rawToChar(data.bin) > Error in rawToChar(data.bin) : > embedded nul in string: > 'X\n\0\0\0\002\0\003\0\001\0\002\003\0\0\0\003\023\0\0\0\005\0\0\0\016\0\0\0\x96@\024ffffff@\023\x99\x99\x99\x99\x99\x9a@\022\xcc\xcc\xcc\xcc\xcc\xcd@\022ffffff@\024\0\0\0\0\0\0@\025\x99\x99\x99\x99\x99\x9a@\022ffffff@\024\0\0\0\0\0\0@\021\x99\x99\x99\x99\x99\x9a@\023\x99\x99\x99\x99\x99\x9a@\025\x99\x99\x99\x99\x99\x9a@\023333333@\023333333@\021333333@\027333333@\026\xcc\xcc\xcc\xcc\xcc\xcd@\025\x99\x99\x99\x99\x99\x9a@\024ffffff@\026\xcc\xcc\xcc\xcc\xcc\xcd@\024ffffff@\025\x99\x99\x99\x99\x99\x9a@\024ffffff@\022ffffff@\024ffffff@\023333333@\024\0\0\0\0\0\0@\024\0\0\0\0\0\0@\024\xcc\xcc\xcc\xcc\xcc\xcd@\024\xcc\xcc\xcc\xcc\xcc\xcd@\022\xcc\xcc\xcc\xcc\xcc\xcd@\023333333@\025\x99\x99\x99\x99\x99\x9a@\024\xcc\xcc\xcc\xcc\xcc\xcd@\026\0\0\0\0\0\0@\023\x99\x99\x99\x99\x99\x9a@\024\0\0\0\0\0\0@\026\0\0\0\0\0\0@\023\x99\x99\x99\x99\x99\x9a@\021\x99\x99\x99\x99\x99\x9a@\024ffffff@\024\0\0\0\0\0\0@\022\0\0\0\0\0\0@\021\x99\x99\x99\x99\x99\x9a@\024\0\0\0\! 0\! > 0\0 > > I don't know what this error should tell me. Then I tried to use the ASCII > format > > data.ascii <- serialize(iris, NULL, ascii = TRUE) > data.raw <- rawToChar(data.ascii) > dbSendQuery(db, "DELETE FROM frames") > dbSendQuery(db, paste("INSERT INTO frames VALUES(1, X'", data.raw, "')", sep > = "")) > Error in sqliteExecStatement(conn, statement, ...) : > RS-DBI driver: (error in statement: unrecognized token: "X'A > > This also does not work. It seems the driver does not deal that nicely with > the regular INSERT query for BLOB objects in SQLite. Then I used a simpler > way: > > dbSendQuery(db, "DELETE FROM frames") > dbSendQuery(db, "DROP TABLE frames") > dbSendQuery(db, 'CREATE TABLE frames("simID" INT, "data" TEXT DEFAULT NULL)') > dbSendQuery(db, paste("INSERT INTO frames VALUES(1, '", data.raw, "')", sep = > "")) > data.bin2 <- dbGetQuery(db, "SELECT data FROM frames WHERE simID = 1") > > Nice, that worked. Now I want to unserialize the data: > > unserialize(data.bin2) > Error in unserialize(data.bin2) : 'connection' must be a connection > > unserialize(data.bin2[1, 'data']) > Error in unserialize(data.bin2[1, "data"]) : > character vectors are no longer accepted by unserialize() > > I feel a little stuck here, but I am very sure, that converting data.frames > to binary data and storing them to a database is not that unusual. So I hope > somebody has already done this and could give me the missing piece. > > > Best > > Simon > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. - - - - - Der NSA keine Chance: e-mail verschluesseln! http://www.gpg4win.org/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.