DATA MIGRATION

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DATA MIGRATION

• Applied Database II

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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

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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.

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Background Activities

• Detail Activity plan for each phase
• Identify Resources
• Define Roles and Responsibilities
• Identify the Migration Tool

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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

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Background Activities

• Prepare Data Extraction Tool
• Prepare Data Volume Analysis Tool
• Prepare Data Mappings

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Background Activities

• Build Cross Reference Tables
• Preparing Data Preparation Queries
• Preparing Business Rules Validation Tools
• Prepare Migration Validation Tools

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Background Activities

• Document Scope
• Document Migration Strategy
• Document Data Preparation Operational Procedures
• Document Migration Validation Operational
  Procedures
• Document Quality Procedures
• Exception Reporting

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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

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Managerial Consideration

• Phased or Big Bang?
• Expectation
• Rollback
• Scalability
• Replication

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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

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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?

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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

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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

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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?

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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

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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

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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

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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

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Documentation
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• 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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