To install JavaCC, navigate to the download directory and type:
$ unzip javacc-7.0.9.zip
$ tar xvf javacc-7.0.9.tar.gz
Then place the binary javacc-7.0.9.jar in a new target/ folder, and rename to javacc.jar.
Once you have completed installation add the scripts/ directory in the JavaCC installation to your PATH. The JavaCC, JJTree, and JJDoc invocation scripts/executables reside in this directory.
INSERT INTO table2 (Id1, @Id)
select @Id1,@Id from table3
where table3.BBId = @BBId AND table3.Flag= 0 and
table3.Id1 = @Id1
You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.
We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!
Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and your IDE will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.
But we can't do that - we can't run your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!
foreach (var entityType in dbContext.Model.GetEntityTypes())
var tableName = entityType.GetTableName();
foreach (var propertyType in entityType.GetProperties())
var columnName = propertyType.GetColumnName();