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IICS:SCD Type2 using MD5 Hashing

#iics #scdt2 #etlguru IICS:SCD Type2 using MD5 Hashing Slowly Changing Dimensions enable the historic aspect of data in an analytical system. It is used in Datawarehouse There are 6 types of Slowly Changing Dimension that are commonly used. In reality, only types 0, 1 and 2 are widely used, and others are reserved for very specific requirements. A Type 2 SCD retains the full history of values. When the value of a chosen attribute changes, the current record is closed. A new record is created with the changed data values and this new record becomes the current record. Each record contains the effective date and expiration date to identify the period between which the record was active. SRC E_ID,E_NAME,E_SALARY,E_DEPT_ID 100,Naganth,60000,10 101,Vinod,80000,10 102,Antosh,50000,11 103,Krishna,70000,12 104,Mahadev,80000,13 105,Mahesh,40000,15 TGT CREATE TABLE EMPLOYEES_SCDT2( emp_key number(6), emp_id number(6), emp_name varchar2(20), emp_salary number(8,2), emp_dept_id number(4), start_date date, end_date date, checksum varchar2(50)); LKPQuery SELECT emp_key as LKP_EMP_KEY, emp_id as LKP_EMP_ID, checksum AS LKP_CHECKSUM FROM EMPLOYEES_SCDT2 Expression o_checksum=MD5(E_ID||E_NAME||E_SALARY||E_DEPT_ID) o_startdate=SYSDATE o_enddate = to_date('9999-12-31','YYYY-MM-DD') o_up_enddate=SYSDATE RTR INSERT = ISNULL(LKP_EMP_KEY) UPSERT = o_checksum!=LKP_CHECKSUM