Sql server RODBC使用sqlSave对MS SQL失去数字列的精度(并在日期失败)
为什么RODBC在使用sqlSave保存到ms sql时会丢失我的数字列的精度 数字 在R中,我使用一个数字列创建以下数据帧。它们可能看起来已经四舍五入了,但这是一个印刷问题,它们不是四舍五入的Sql server RODBC使用sqlSave对MS SQL失去数字列的精度(并在日期失败),sql-server,r,rodbc,significant-digits,Sql Server,R,Rodbc,Significant Digits,为什么RODBC在使用sqlSave保存到ms sql时会丢失我的数字列的精度 数字 在R中,我使用一个数字列创建以下数据帧。它们可能看起来已经四舍五入了,但这是一个印刷问题,它们不是四舍五入的 >test <- data.frame( id=c(1,2,3), numbers=c(12345678.90,12345678.91,12345678.92) ) > str(test) 'data.frame': 3
>test <- data.frame(
id=c(1,2,3),
numbers=c(12345678.90,12345678.91,12345678.92)
)
> str(test)
'data.frame': 3 obs. of 2 variables:
$ id : num 1 2 3
$ numbers: num 12345679 12345679 12345679
> test$numbers==123456789
[1] FALSE FALSE FALSE
日期
日期类列导致浮点类型的ms sql列,从而导致存储不正确的值:
> test <- data.frame(id=c(1,2,3),date=as.Date(c("2014-12-21","2014-12-22","2014-12-23")))
> sqlSave(dbconn, test, fast=F, verbose=T)
Query: CREATE TABLE "test" ("rownames" varchar(255), "id" float, "date" float)
Query: INSERT INTO "test" ( "rownames", "id", "date" ) VALUES ( '1', 1, 2014-12-21 )
Query: INSERT INTO "test" ( "rownames", "id", "date" ) VALUES ( '2', 2, 2014-12-22 )
Query: INSERT INTO "test" ( "rownames", "id", "date" ) VALUES ( '3', 3, 2014-12-23 )
> test2<-sqlFetch(dbconn, "test")
> test2
id date
1 1 1981
2 2 1980
3 3 1979
在RODBC的代码中,似乎有内部调用在as.matrix.dataframe中取消列表,这可以解释这个问题:
> unlist(list(test))
id1 id2 id3 numbers1 numbers2 numbers3
1 2 3 12345679 12345679 12345679 '
我最好的嘉宾是围绕RODBC工作,并作为varType逻辑控制到字符的转换
逻辑列被解释为varchar,我们可以很容易地将其转换为BIT
sqlSave2<-function(dbconn, dat, tablename = NULL, ...){
# get the name of the variable passed as dat, taken from sqlSave implementation
if (is.null(tablename))
tablename <- if (length(substitute(dat)) == 1)
as.character(substitute(dat))
else as.character(substitute(dat)[[2L]])
if (length(tablename) != 1L)
stop(sQuote(tablename), " should be a name")
varTypes <- sapply(dat, function(x){
if(is.numeric(x)){
"float"
}else if(is.factor(x)|is.character(x)){
paste0("[varchar](",max(nchar(as.character(x))),")")
} else if(is.logical(x)){"BIT"} else if("Date"%in%class(x)) {
"date"
} else if ("POSIXt"%in%class(x)){
"smalldatetime"
}else{NA}})# let RODBC determine
varTypes <- varTypes[!is.na(varTypes)]
dat2<-as.data.frame(sapply(dat, function(x){
if(is.numeric(x)){
x2<-sprintf("%.15e",x)
if(sum(is.na(x))>0)
x2[is.na(x)]<-NA
x2
} else if(is.logical(x)){
x2<-rep(0,length(x))
x2[!is.na(x) & x==T]<-1
if(sum(is.na(x))>0)
x2[is.na(x)] <- NA
x2
} else as.character(x)
}))
sqlSave(dbconn, dat2, tablename, fast=FALSE, varTypes=varTypes, ...)
}
以下是:
> sqlSave2(dbconn, test)
Query: CREATE TABLE "test" ("rownames" varchar(255), "id" float, "date" date, "datetime" smalldatetime)
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '1', 1.234567891200000e+08, N'2014-12-21', '2014-12-21 10:00:00' )
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '2', 1.234567892300000e+08, N'2014-12-22', '2014-12-22 11:00:00' )
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '3', 1.234567892300000e+08, N'2014-12-23', '2014-12-23 12:00:00' )
通过以下验证:
> test2<-sqlFetch(dbconn, "test")
> test2
id date datetime
1 123456789 2014-12-21 2014-12-21 10:00:00
2 123456789 2014-12-22 2014-12-22 11:00:00
3 123456789 2014-12-23 2014-12-23 12:00:00
> str(test2)
'data.frame': 3 obs. of 3 variables:
$ id : num 1.23e+08 1.23e+08 1.23e+08
$ date : Factor w/ 3 levels "2014-12-21","2014-12-22",..: 1 2 3
$ datetime: POSIXct, format: "2014-12-21 10:00:00" "2014-12-22 11:00:00" "2014-12-23 12:00:00"
> test2$id==123456789
[1] FALSE FALSE FALSE
>test2 test2
id日期日期时间
1 123456789 2014-12-21 2014-12-21 10:00:00
2 123456789 2014-12-22 2014-12-22 11:00:00
3 123456789 2014-12-23 2014-12-23 12:00:00
>str(test2)
“data.frame”:3个obs。共有3个变量:
$id:num 1.23e+08 1.23e+08 1.23e+08
$date:系数w/3等级“2014-12-21”、“2014-12-22”、..:1 2 3
$datetime:POSIXct,格式:“2014-12-21 10:00:00”“2014-12-22 11:00:00”“2014-12-23 12:00:00”
>test2$id==123456789
[1] 假假假假
> packageVersion("RODBC")
[1] ‘1.3.10’
> unlist(list(test))
id1 id2 id3 numbers1 numbers2 numbers3
1 2 3 12345679 12345679 12345679 '
sqlSave2<-function(dbconn, dat, tablename = NULL, ...){
# get the name of the variable passed as dat, taken from sqlSave implementation
if (is.null(tablename))
tablename <- if (length(substitute(dat)) == 1)
as.character(substitute(dat))
else as.character(substitute(dat)[[2L]])
if (length(tablename) != 1L)
stop(sQuote(tablename), " should be a name")
varTypes <- sapply(dat, function(x){
if(is.numeric(x)){
"float"
}else if(is.factor(x)|is.character(x)){
paste0("[varchar](",max(nchar(as.character(x))),")")
} else if(is.logical(x)){"BIT"} else if("Date"%in%class(x)) {
"date"
} else if ("POSIXt"%in%class(x)){
"smalldatetime"
}else{NA}})# let RODBC determine
varTypes <- varTypes[!is.na(varTypes)]
dat2<-as.data.frame(sapply(dat, function(x){
if(is.numeric(x)){
x2<-sprintf("%.15e",x)
if(sum(is.na(x))>0)
x2[is.na(x)]<-NA
x2
} else if(is.logical(x)){
x2<-rep(0,length(x))
x2[!is.na(x) & x==T]<-1
if(sum(is.na(x))>0)
x2[is.na(x)] <- NA
x2
} else as.character(x)
}))
sqlSave(dbconn, dat2, tablename, fast=FALSE, varTypes=varTypes, ...)
}
> test <- data.frame(
id=c(123456789.12,123456789.23,123456789.23),
date=as.Date(c("2014-12-21","2014-12-22","2014-12-23")),
datetime=as.POSIXlt(c("2014-12-21 10:00","2014-12-22 11:00","2014-12-23 12:00")))
> str(test)
'data.frame': 3 obs. of 3 variables:
$ id : num 1.23e+08 1.23e+08 1.23e+08
$ date : Date, format: "2014-12-21" "2014-12-22" "2014-12-23"
$ datetime: POSIXct, format: "2014-12-21 10:00:00" "2014-12-22 11:00:00" "2014-12-23 12:00:00"
> sqlSave(dbconn, test, fast=F, verbose=T)
Query: CREATE TABLE "test" ("rownames" varchar(255), "id" float, "date" float, "datetime" float)
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '1', 123456789, 2014-12-21, 2014-12-21 10:00:00 )
Error in sqlSave(dbconn, test, fast = F, verbose = T) :
42000 102 [Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near '10'.
[RODBC] ERROR: Could not SQLExecDirect 'INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '1', 123456789, 2014-12-21, 2014-12-21 10:00:00 )'
> sqlSave2(dbconn, test)
Query: CREATE TABLE "test" ("rownames" varchar(255), "id" float, "date" date, "datetime" smalldatetime)
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '1', 1.234567891200000e+08, N'2014-12-21', '2014-12-21 10:00:00' )
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '2', 1.234567892300000e+08, N'2014-12-22', '2014-12-22 11:00:00' )
Query: INSERT INTO "test" ( "rownames", "id", "date", "datetime" ) VALUES ( '3', 1.234567892300000e+08, N'2014-12-23', '2014-12-23 12:00:00' )
> test2<-sqlFetch(dbconn, "test")
> test2
id date datetime
1 123456789 2014-12-21 2014-12-21 10:00:00
2 123456789 2014-12-22 2014-12-22 11:00:00
3 123456789 2014-12-23 2014-12-23 12:00:00
> str(test2)
'data.frame': 3 obs. of 3 variables:
$ id : num 1.23e+08 1.23e+08 1.23e+08
$ date : Factor w/ 3 levels "2014-12-21","2014-12-22",..: 1 2 3
$ datetime: POSIXct, format: "2014-12-21 10:00:00" "2014-12-22 11:00:00" "2014-12-23 12:00:00"
> test2$id==123456789
[1] FALSE FALSE FALSE