Here I will explain difference between @@identity, scope_identity and ident_current in sql server with example. Generally @@identity, scope_identity and ident_current properties in sql server is used to get identity / id value of last or newly inserted record in table but only difference is scope either local or global and session either current session or other session in sql server.
In previous posts I explained cursor with example in sql server, difference b/w stored procedure and function in sql server, handle exceptions in sql server, difference between page_init and page_load events in asp.net, difference between ref and out parameters in c#, constructors in c#, vb.net with examples, delegates in c# with example, difference between len and datalength in sql server and many articles relating to interview questions, asp.net, c#.net. Now I will explain difference between @@identity, scope_identity and ident_current in sql server with example.
It will return last or newly inserted record id of any table in current session but it’s not limited to current scope. In current session if any trigger or functions inserted record in any table that it will return that latest inserted record id regardless of table. We need to use this property whenever we don’t have any other functions or triggers that run automatically.
This property will return last or newly inserted record id of table in current session or connection and it’s limited to current scope that means it will return id of newly inserted record in current session / connection stored procedure or query executed by you in current scope even we have any other functions or triggers that run automatically. Its better we can go with property whenever we need to get last or newly inserted record id in table.
This property will return last or newly inserted record id of specified table. It’s not limited to any session or scope it’s limited to mentioned table so it will return last inserted record id of specified table.
Finally we can say SCOPE_IDENTITY properties is best to get newly inserted record id from executed stored procedure or query when compared with other properties
CREATE TABLE SAMPLE1 (Id INT IDENTITY)
CREATE TABLE SAMPLE2 (Id INT IDENTITY(100,1))
-- Trigger to execute while inserting data into SAMPLE1 table
CREATE TRIGGER TRGINSERT ON SAMPLE1 FOR INSERT
INSERT SAMPLE2 DEFAULT VALUES
SELECT * FROM SAMPLE1 -- It will return empty value
SELECT * FROM SAMPLE2 -- It will return empty value
When we execute above statements we will get output like as shown below
Now we will insert default values in “SAMPLE1” table by executing following query and check values of @@identity, scope_identity() and ident_current(‘tablenae’)
INSERT SAMPLE1 DEFAULT VALUES
SELECT @@IDENTITY -- It returns value 100 this was inserted by trigger
SELECT SCOPE_IDENTITY() -- It returns value 1 this was inserted by insert query in SAMPLE1
SELECT IDENT_CURRENT('SAMPLE2') -- It returns value inserted in SAMPLE2 table
Our output will be like as shown below