According to the Microsoft documentation for the DATETIME column type, values of that type can store "accuracy rounded to increments of .000, .003, or .007 seconds." According to their documentation for the data types used by ADODB, the adDBTimeStamp (code 135), which ADODB uses for DATETIME column parameters, "indicates a date/time stamp (yyyymmddhhmmss plus a fraction in billionths)." However, all attempts (tested using multiple versions of SQL Server, and both the SQLOLEDB provider and the newer SQLNCLI11 provider) fail when a parameter is passed with sub-second precision. Here's a repro case demonstrating the failure:
import win32com.client
# Connect to the database
conn_string = "Provider=...." # sensitive information redacted
conn = win32com.client.Dispatch("ADODB.Connection")
conn.Open(conn_string)
# Create the temporary test table
cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = conn
cmd.CommandText = "CREATE TABLE #t (dt DATETIME NOT NULL)"
cmd.CommandType = 1 # adCmdText
cmd.Execute()
# Insert a row into the table (with whole second precision)
cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = conn
cmd.CommandText = "INSERT INTO #t VALUES (?)"
cmd.CommandType = 1 # adCmdText
params = cmd.Parameters
param = params.Item(0)
print("param type is {:d}".format(param.Type)) # 135 (adDBTimeStamp)
param.Value = "2018-01-01 12:34:56"
cmd.Execute() # this invocation succeeds
# Show the result
cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = conn
cmd.CommandText = "SELECT * FROM #t"
cmd.CommandType = 1 # adCmdText
rs, rowcount = cmd.Execute()
data = rs.GetRows(1)
print(data[0][0]) # displays the datetime value stored above
# Insert a second row into the table (with sub-second precision)
cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = conn
cmd.CommandText = "INSERT INTO #t VALUES (?)"
cmd.CommandType = 1 # adCmdText
params = cmd.Parameters
param = params.Item(0)
print("param type is {:d}".format(param.Type)) # 135 (adDBTimeStamp)
param.Value = "2018-01-01 12:34:56.003" # <- blows up here
cmd.Execute()
# Show the result
cmd = win32com.client.Dispatch("ADODB.Command")
cmd.ActiveConnection = conn
cmd.CommandText = "SELECT * FROM #t"
cmd.CommandType = 1 # adCmdText
rs, rowcount = cmd.Execute()
data = rs.GetRows(2)
print(data[0][1])
This code throws an exception on the line indicated above, with the error message "Application uses a value of the wrong type for the current operation." Is this a known bug in ADODB? If so, I haven't found any discussion of it. (Perhaps there was discussion earlier which disappeared when Microsoft killed the KB pages.) How can the value be of the wrong type if it matches the documentation?
