What does N and U stand for and what are its meaning while finding an object

Question

IF OBJECT_ID (N'dbo.AWBuildVersion', N'U') IS NOT NULL
DROP TABLE dbo.AWBuildVersion;

I don't understand what N and U are for in SQL server ?

Thanks

Answer 1

• U stands for Table (user-defined). Check here for more info. The syntax OBJECT_ID is

  OBJECT_ID ( '[ database_name . [ schema_name ] . | schema_name . ] 
  object_name' [ ,'object_type' ] )
  

  here Object_type = 'U' which denotes Table (user-defined)

• N Makes the String to be considered as nvarchar data type. It denotes that the subsequent string is in Unicode (the N actually stands for National language character set). Which means that you are passing an NCHAR, NVARCHAR or NTEXT value, as opposed to CHAR, VARCHAR or TEXT.

Answer 2

'U' character stands for itself. The N prefix makes it a one-character UNICODE string. OBJECT_ID procedure expects you to pass one of pre-defined one-character values for the second parameter, which needs to be a UNICODE string.

This syntax is used to create literals with characters in other encodings, for example

CREATE TABLE hello_world (str NVARCHAR(20))
INSERT INTO hello_world (str) VALUES (N'Здравствуй, мир!')