R DBI ODBC error: nanodbc/nanodbc.cpp:3110: 07009: [Microsoft][ODBC Driver 13 for SQL Server]Invalid Descriptor Index

问题

I continue to read the DBI/ODBC is faster than RODBC, so I tried as follows:

require(DBI);require(odbc)
con <- DBI::dbConnect(odbc::odbc(), dsn = 'SQLSERVER1', database = 'AcumaticaDB')

I can make a successful connection to the DSN, but the following query:

rs <- dbGetQuery(con, "SELECT * FROM inventoryitem")
dbFetch(rs)

gives me the following error:

Error in result_fetch(res@ptr, n, ...) : nanodbc/nanodbc.cpp:3110: 07009: [Microsoft][ODBC Driver 13 for SQL Server]Invalid Descriptor Index

What am I doing wrong ? Please, no RODBC solutions. Thanks!

回答1:

rs <- dbGetQuery(con, "SELECT * FROM inventoryitem")
dbFetch(rs)

If inventoryitem table contains mix of long data/variable-length columns (eg. VARBINARY, VARCHAR) and columns of simple types (eg. INT), you can not query them in arbitrary order via ODBC.

Applications should make sure to place long data columns at the end of the select list.

Long data is retrieved from database using ODBC API call SQLGetData and it has to be retrieved after the other data in the row has been fetched.

These are known and documented ODBC restrictions

To retrieve long data from a column, an application first calls SQLFetchScroll or SQLFetch to move to a row and fetch the data for bound columns. The application then calls SQLGetData.

See https://docs.microsoft.com/en-us/sql/odbc/reference/develop-app/getting-long-data

回答2:

There is a workaround:

Reorder your SELECT statements such that longer datatypes (typically strings) are last.

If you have a complex query that is generated by dbply itself, get the SQL query directly via show_query(). Copy-paste and modify the first SELECT statement such that long datatypes are last in the list. It should then work.

EDIT: in many cases it is possible to reorder the fields by adding

%>% select(var1, var2, textvar1, textvar2)

to the query.

回答3:

I have also been struggling with this issue for several months. However, I have come across a solution that may help you as well.

In a nutshell, the issue occurs when certain text columns do not appear after integer/numeric columns. When the columns are not aligned properly in the query, an error of invalid index is thrown and your connection may freeze. The issue then is, how do I know what to put at the end of my query?

To determine this, one could typically examine a column using class() or typeof(). To examine such information from the database, you can use a query such as:

dbColumnInfo(dbSendQuery(con, "SELECT * from schema.table")) # You may not require the schema part...

This will return a table with a type field for every column in the data-set of interest. You can then use this table as an index to sort the select() statement. My particular difficulty is that the type field in the table was all numbers! However, I noticed that every column with a negative number, when placed at the end of the select statement, fixed my query and I could pull the whole table just fine. For example, my full solution:

# Create my index of column types (ref to the current order)
index <- dbColumnInfo(dbSendQuery(con, "SELECT * from schema.table"))
index$type <- as.integer(index$type) # B/c they are + and - numbers!

# Create the ref to the table
mySQLTbl <- tbl(con, in_schema("schema", "tablename"))

# Use the select statement to put all the + numbered columns first!
mySQLTbl %>%
  select(c(which(index$type>=0),
                 which(index$type<0)))

As for reason for why this occurs, I am not sure and I do not have the data access privileges to dig much deeper in my use-case

回答4:

I got this error as a result of trying to load in a timestamp variable. Try removing any timestamp variables from your query.

Try the below or similar. Let me know what works and I'll update my post.

require(DBI);require(odbc)
con <- DBI::dbConnect(odbc::odbc(), dsn = 'SQLSERVER1', database = 'AcumaticaDB')

column.types = DBI::dbGetQuery( 
    con, 
    'SELECT COLUMN_NAME, DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = "inventoryitem"' 
))

sql = paste(c(
        'select ', 
        paste(column.types$COLUMN_NAME[column.types$DATA_TYPE != 'timestamp'], collapse = ', '), 
        ' from inventoryitem'
     ),
    collapse = ''
)

dbFetch(dbGetQuery(con, sql))

来源：https://stackoverflow.com/questions/45001152/r-dbi-odbc-error-nanodbc-nanodbc-cpp3110-07009-microsoftodbc-driver-13-fo

标签

sql-server

odbc

r-dbi

nanodbc