DATA MIGRATION Applied Database II DEFINITION Data migration
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 § 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
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