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如何使用odbc进行“Select*from”查询

odbc sql-server r

Matthew · 技术社区 · 7 年前

我用的是 odbc package 在R中,我有一个SQL Server数据库,其中的表具有 Name 列,即 nvarchar(max) PublishStatus 是整数的列。

此代码无效:

library(odbc)
library(DBI)
library(tidyverse)
con_string="Driver=ODBC Driver 11 for SQL Server;Server=myServer; Database=MyDatabase; trusted_connection=yes"
con=dbConnect(odbc::odbc(), .connection_string =con_string)
query="select * from MyTable"
result=NULL
result=dbSendQuery(con,query) %>% dbFetch
head(result)

它只是产生错误信息

获取结果时出错(res@ptr,n,…): nanodbc/纳米dbc。cpp:2890:07009:[Microsoft][ODBC Driver 11 for SQL Server]描述符索引无效

如果我再次尝试查询,会收到另一条错误消息,并且我可以告诉您,如果不关闭R并重新打开,就无法恢复:

nanodbc/纳米dbc。cpp:1587:HY000:[Microsoft][ODBC Driver 11 for SQL Server]连接正忙,另一个命令的结果

因为R和R的odbc都是非常糟糕的名称,所以很难搜索这个包中的错误。在 this SO 似乎列的顺序很重要,它要求在查询中首先指定整数列。

query="select PublishStatus,Name from MyTable"
result=NULL
result=dbSendQuery(con,query) %>% dbFetch
head(result)

但这并不是:

query="select Name,PublishStatus from MyTable"
result=NULL
result=dbSendQuery(con,query) %>% dbFetch
head(result)

select *

有什么办法让我可以做吗询问?
当我拿到 Invalid Descriptor Index 错误,有没有一种方法可以在不重新启动R的情况下进行恢复?

:使用旧的RODBC库,即使使用相同的ODBC驱动程序,它也没有此缺陷。这适用于 select * from 查询,并且不关心列的顺序

library(RODBC)
con=odbcDriverConnect(ConnectionString_Hemonc)  
result=sqlQuery(con,query,stringsAsFactors=FALSE)
close(con)
head(result)

我之前放弃了RODBC因为 it is unable (in practice) to write data to a database, as I discovered here .

odbc 为了更快地读取数据,它的一个副作用是现在对读取数据的顺序非常挑剔。不幸的是,这破坏了我的用例——我不能要求只懂基本SQL的人使用将完全有效的SQL视为无效的工具。

我想是的 RODBC 用于读取数据,

:我试过了 ODBC Driver 13 for SQL Server 在连接字符串中而不是 ODBC Driver 11

1 回复 | 直到 7 年前

Suraj Kumar zip 6 年前

Getting Data From Excel and SQL Server using ODBC

set-psdebug -strict
$ErrorActionPreference = "stop" 

$ExcelFilePath='MyPath\pubs.xlsx' #the full path of the excel workbook
if (!(Test-Path $ExcelFilePath))
 {
 Write-Error "Can't find '$($ExcelFilePath)'. Sorry, can't proceed because of this"
 exit
 }

try {
$Connection = New-Object system.data.odbc.odbcconnection
$Connection.ConnectionString = 'Driver={Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)};DBQ='+$ExcelFilePath+'; Extended Properties="Mode=ReadWrite;ReadOnly=false; HDR=YES"' 
$Connection.Open()
}
catch
{
 $ex = $_.Exception
 Write-Error "whilst opening connection to $ExcelFilePath : Sorry, can't proceed because of this"
 exit
}

try { 
$Query = New-Object system.data.odbc.odbccommand
$Query.Connection = $connection
$Query.CommandText = @'
SELECT title, SUM(qty) AS sales,
 COUNT(*) AS orders
 FROM [titles$] t
 INNER JOIN [sales$] s ON t.title_id=s.title_id
 WHERE title like '%?'
 GROUP BY title
 ORDER BY SUM(qty) DESC
'@ 

$Reader = $Query.ExecuteReader([System.Data.CommandBehavior]::SequentialAccess) #get the datareader and just get the result in one gulp
}
catch
{
 $ex = $_.Exception
 Write-Error "whilst executing the query '$($Query.CommandText)' $ex.Message Sorry, but we can't proceed because of this!"
 $Reader.Close()
 $Connection.Close()
 Exit;
}

Try
{
$Counter = $Reader.FieldCount #get it just once
$result=@() #initialise the empty array of rows
 while ($Reader.Read()) {
 $Tuple = New-Object -TypeName 'System.Management.Automation.PSObject'
 foreach ($i in (0..($Counter - 1))) {
 Add-Member `
 -InputObject $Tuple `
 -MemberType NoteProperty `
 -Name $Reader.GetName($i) `
 -Value $Reader.GetValue($i).ToString()
 }
 $Result+=$Tuple
 }
 $result | Format-Table 
 }
catch
{
 $ex = $_.Exceptio
 Write-Error "whilst reading the data from the datatable. $ex.Message"
}
$Reader.Close()
$Connection.Close()