Sql server 如何从dplyr管道创建SQL Server表

由于，

copy_to

和

compute

当前不适用于SQL Server连接

connStr <- "driver=ODBC Driver 13 for SQL Server;server=localhost;..."
db <- DBI::dbConnect(odbc::odbc(), .connection_string=connStr)

copy_to(db, mtcars)
#Error: <SQL> 'CREATE TEMPORARY TABLE "mtcars" (
#  "row_names" varchar(255),
#  "mpg" FLOAT,
#  ...
#  nanodbc/nanodbc.cpp:1587: 42000: [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]Unknown object type 'TEMPORARY' used in a CREATE, DROP, or ALTER statement. 

# use raw DBI functionality to create table
DBI::dbWriteTable(db, "mtcars", mtcars)

qry <- tbl(db, "mtcars") %>% group_by(am) %>% summarise(m=mean(mpg))

compute(qry)
#Error: <SQL> 'CREATE TEMPORARY TABLE "isrxofsskr" AS SELECT "am" AS "am", "m" #AS "m"
#FROM (SELECT "am", AVG("mpg") AS "m"
#FROM "mtcars"
#GROUP BY "am") "htrkkxabrn"'
#  nanodbc/nanodbc.cpp:1587: 42000: [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]Unknown object type 'TEMPORARY' used in a CREATE, DROP, or ALTER statement. 

---

connStr事实证明，dbplyr repo上的PR无论如何都会出错，并且会在写回之前将整个表拉入内存

解决这个问题需要为dbplyr泛型创建两个特定于MSSQL的方法。下面列出了这些问题。我还将它们发布到dbplyr回购协议上，因此（假设它们有效）它们应该很快被合并

#' @export
`db_compute.Microsoft SQL Server` <- function(con, table, sql, temporary=TRUE,
     unique_indexes=list(), indexes=list(), ...)
{
    # check that name has prefixed '##' if temporary
    if(temporary && substr(table, 1, 1) != "#")
        table <- paste0("##", table)

    if(!is.list(indexes))
        indexes <- as.list(indexes)

    if(!is.list(unique_indexes))
        unique_indexes <- as.list(unique_indexes)

    db_save_query(con, sql, table, temporary=temporary)
    db_create_indexes(con, table, unique_indexes, unique=TRUE)
    db_create_indexes(con, table, indexes, unique=FALSE)
    table
}


#' @export
`db_save_query.Microsoft SQL Server` <- function(con, sql, name, temporary=TRUE, ...)
{
    # check that name has prefixed '##' if temporary
    if(temporary && substr(name, 1, 1) != "#")
        name <- paste0("##", name)

    tt_sql <- build_sql("SELECT * INTO ", ident_q(name),
                        " FROM (", sql, ") ", ident_q(name), con=con)

    dbExecute(con, tt_sql)
    name
}

导出
`db_compute.Microsoft SQL Server`@Hack-R正确。理想情况下，我希望能够选择是创建永久表还是临时表。嘿，这可能是一个愚蠢的问题，但由于错误只是SQL语法有点不正确，我们是否可以稍微编辑包源代码来修复它？我认为您只需要删除单词“TEMPORARY”（或者使用pull请求中的代码，可能通过在其中合并fork，然后使用install\u github安装fork？）。