Question

我正在尝试使用JDBC驱动程序将R与Netezza连接。

我设法成功连接数据库，但结果不是正确的。

# Here are the connection details
library(RJDBC)
drv <- JDBC(driverClass="org.netezza.Driver", classPath = "C://JDBC//nzjdbc.jar", "'")
con <- dbConnect(drv, "jdbc:netezza://10.206.0.66:5480//DBASE", "USER", "PASS")

# > con
# An object of class "JDBCConnection"
# Slot "jc":
# [1] "Java-Object{org.netezza.sql.NzConnection@bce3d7}"

# Slot "identifier.quote":
# [1] "'"

res <- dbSendQuery(con, "SELECT * FROM DBASE.MARBEL.DATOS limit 10000;")
res <- fetch(res, n = -1)

问题是字段被重新列为具有“垂直”变量的列表而不是表的列！

head(res)

SUBSCRIPTION_ID
1 245206318120314                                                                                                                                                                                                                                                
2 235109338101206                                                                                                                                                                                                                                                
3 238463669110624                                                                                                                                                                                                                                                
4 214177015090830                                                                                                                                                                                                                                                
5 212403495090830                                                                                                                                                                                                                                                
6 13874138618090824                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                   SUB_ACCOUNT_ID
1 MV_SUBCTA_45206318_20120316                                                                                                                                                                                                                                    
2 MV_SUBCTA_35109338_20101207                                                                                                                                                                                                                                    
3 MV_SUBCTA_38463669_20110627                                                                                                                                                                                                                                    
4 MV_SUBCTA_45223848_20120316                                                                                                                                                                                                                                    
5 MV_SUBCTA_12403495_20081224                                                                                                                                                                                                                                    
6 MV_SUBCTA_18932919_20091012                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                       ACCOUNT_ID
1 MV_CTA_44123765_20120316                                                                                                                                                                                                                                       
2 MV_CTA_35213277_20101207                                                                                                                                                                                                                                       
3 MV_CTA_37772612_20110627                                                                                                                                                                                                                                       
4 MV_CTA_14217213_20090330                                                                                                                                                                                                                                       
5 MV_CTA_12477560_20081224                                                                                                                                                                                                                                       
6 MV_CTA_18758944_20091012                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                 ACCESS_METHOD_ID
1 1167391804                                                                                                                                                                                                                                                     
2 1159354610                                                                                                                                                                                                                                                     
3 2966407995                                                                                                                                                                                                                                                     
4 1153360304                                                                                                                                                                                                                                                     
5 1131960835                                                                                                                                                                                                                                                     
6 3874138618

知道怎么解决这个问题？我有一个有效的ODBC连接，但我宁愿使用JDBC。

Answer 1

我将输出一直向右滚动，看起来列中的字符串非常宽（它们是CHAR而不是VARCHAR吗？），因此结果不符合R控制台的宽度。因此R以这种方式显示它们。

因此，请尝试在查询中修剪它们

select rtrim(SUB_ACCOUNT_ID), ...

或在R：

require('stringr')
res$SUB_ACCOUNT_ID <- str_trim(res$SUB_ACCOUNT_ID)

Answer 2

根据Alex的回答，我写了这个函数，在所有变量中使用rtrim。

query_nzz <- function(con, select="select * ", from="", where = "", limit = " 10000; "){
  options(scipen=666)

  # Get variable Names
  query_names = paste(select, " from ",from, where, sep = " ")
  names <- dbGetQuery(con, paste(query_names,"limit 1;", sep= " "))
  names <- names(names)

  # Trim spaces
  select <- paste0("trim(",names,") as ", names, collapse = ",")

  query = paste0("select ", select, " from ", from, where, " limit ",deparse(limit),";")
  data = dbGetQuery(con, query)
  data
}

功能用途

  dt <- query_nzz(
    con,
    select = "select * ",
    from = "DATABASE.TABLENAME",
    where = "",
    limit = 100000
  )

使用RJDBC连接R和Netezza

2 个答案: