DATA MIGRATION Applied Database II

DEFINITION   Data migration is a set of activities that moves data from one or more legacy systems to a new application   Data migration can be in level of :   Machine   Application   Data

Background  Updating the user-interface of application, adding or updating the function of an application in the same machine with same data  Migrating to new machine  Restructuring data in an application  Updating application, restructuring tables, and moving to new machine.

Background Activities   Detail Activity plan for each phase   Identify Resources   Define Roles and Responsibilities   Identify the Migration Tool

Background Activities   Identify Scope of Automated Migration   Identify the Data Preparation/Cleanup Needs   Identify Cross Reference Tables   Migration Validation Strategy   Define Procedure for setting up Master Codes

Background Activities   Prepare Data Extraction Tool   Prepare Data Volume Analysis Tool   Prepare Data Mappings

Background Activities   Build Cross Reference Tables   Preparing Data Preparation Queries   Preparing Business Rules Validation Tools   Prepare Migration Validation Tools

Background Activities   Document Scope   Document Migration Strategy   Document Data Preparation Operational Procedures   Document Migration Validation Operational Procedures   Document Quality Procedures   Exception Reporting

Steps  In principle, the migration of a system should not interfere with operation of system.  Steps should be done is  Migration planning  Migrating  Migration documentation  Acceptance with User

Managerial Consideration  Phased or “Big Bang”?  Expectation  Rollback  Scalability  Replication

Phased or “Big Bang”?  Migrating all at once or  Moving data over one piece at a time  Some considerations :  How much data there is to migrate  The amount of effort for a big bang

Expectations  How long will the migration take?  How many internal resources must one commit?  For what period of time?  What is the level of expertise needed from external sources?  What is the cost?

Rollback  What happens if the data migration fails?  Using existing transcation rollback functionality or having capacity to design and build a new one?  Providing an additional layer of security  Helps reducing development costs

Scalability  Is our current system going to support our growth plan in the next years?  What if we purchase another company and want to migrate their data into our system

Replication  What happens in case of disaster or irrecoverable system failure?  Migrating data to a backup system at the same time as a new target system?

Migration planning  For data  Table structure of older application (table specification), should not re-type but drawn from definitions of existing systems  Table structure of new application  Mapping of each field from the old to the new table and rules  Utilities are required to perform the data migration

Migration planning  For Applications:  List of functions available on the old application  List of functions available on a new application  Old and new mapping functionality, with the necessary records

Migration planning  For Machines  Characteristics of a new engine for applications that run on old machines  Things that should be done because the change machine  Utilities required

Migration Implementation  All data should be recorded in volume  Data migration can often be assisted with tools and  Examples of planning documents and implementation of migration can be seen in the attached document

Documentation

Catatan : Field (Nama, type, length) tabel asal tidak diketik, tetapi diambil dari dokumentasi sistem! Pada kolom “Aturan” disebutkan aturan pemindahan data, apakah “apa adanya” (hanya boleh jika field asal dan tujuan identik), ataukah harus dilakukan transformasi Jika lebar dan type field tidak sama, maka Kolom “Aturan” harus diisi dengan jelas