Chapter 12: Data and Database Administration

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Chapter 12 Data and Database Administration
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Data Administrator

• Custodian of the organizations data
• Develops procedures to protect and control data
  resource
  
• Maintains corporate-wide data definitions and
  standards
  
• Functional responsibilities planning, analysis,
  design, implementation, maintenance, protection
  
• Should be a respected, senior-level middle
  manager
  
• Requires a high level of managerial and technical
  skills

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Database Administrator

• Responsible for physical database design and
  technical issues
  
• Carries through the standards and procedures
  established by data administrator
  
• Broad technical background
• Managerial skills are also critical

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Corporate Data Management

• Functions
• data policies, procedures, and standards
• planning
• data conflict resolution
• internal marketing
• managing the data repository
• selection of hardware and software
• managing data security, privacy, and integrity
• data backup and recovery

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Planning for Databases

• What data will be included?
• What processes will the system perform?
• What business locations will the system affect?
• What work units and people will be affected by
  the system?
  
• How will the system fit with significant business
  effects?

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Managing Data Security

• Threats to data security
• accidental human, software, hardware error
• theft and fraud
• loss of privacy or confidentiality
• loss of data integrity
• loss of availability
• Data security plan
• limit access
• conceal data
• facilitate recovery

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Security Views

• Presents only data to which a user needs access
• Always shows current data
• More sophisticated security measures are normally
  required

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Security Authorization Rules

• Restrict access to data
• Restrict actions that may be taken
• Authorization tables for subjects (users)
• Authorization tables for objects (data)

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Security User-Defined Procedures
Security Encryption Security Authentication S
chemes
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Database Recovery

• Backup facilities
• static data dynamic data incremental backup
• Journalizing facilities
• transaction log before-image after-image
• Checkpoint facility
• provides known state from which recovery can be
  done
  
• Recovery manager

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Recovery and Restart Procedures

• Switch (mirrored database)
• Restore/Rerun reprocess transactions
• Transaction integrity
• commit or abort
• backward recovery rollback undo transactions
• forward recovery -- rollforward apply
  transactions

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Chapter 13 Distributed Databases
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Distributed Database

• A single logical database that is spread
  physically across computers in multiple locations
  that are connected by a data communications
  network.
• conditions that encourage use of distributed
  databases
  
• distribution and autonomy of business units
• data sharing
• data communications costs and reliability

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Options for Distributing a Database

• Data replication
• Horizontal partitioning
• Vertical partitioning
• Combinations of the above

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Data Replication

• Advantages
• reliability
• fast response
• less complicated integrity routines
• node decoupling
• reduced network traffic at prime time
• Disadvantages
• storage requirements
• complexity and cost of updating

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More on Data Replication

• Schemes
• snapshot replication
• near real-time replication
• pull replication
• Replication favored when
• process requests are read-only
• data are relatively static

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Partitioning (H or V)

• Advantages
• efficiency
• local optimization
• security
• ease of querying
• Disadvantages
• inconsistent access speeds
• backup vulnerability

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