ODP.NET output String parameter does not return value

问题

I was defining a string output parameter in the RETURNING clause of an INSERT statement using ODP.NET. I was not able to get any value returned. It worked fine for other DbTypes.

回答1:

I tracked down the problem as being the following. Oracle seems to require the size parameter to be set for output string parameters to indicate the maximum size of the string to be retrieve. The default (0) causes the output value to be an empty string.

来源：https://stackoverflow.com/questions/27237622/odp-net-output-string-parameter-does-not-return-value