lecture 2

• Two-Tier Architecture Advantages

  • Apps can be developed by users
  • Easy to maintain and modify
  • High performance due to apps and databases being stored together
  • Faster to develop due to less complexity
• Two-Tier Disadvantages

  • Limited users before performance degrades
  • Not adaptable to environments with logic rules, causes slow databases
  • Difficult to have different environments, must follow rules for all versions
  • End users must have different logins for all apps
• 3-Tier Advantages

  • easily scaled
  • High performance due to multiple database servers
  • very flexible with deployment and configuration
  • improved data integrity as data corruption is limited
  • improved security, end users do not have database access
  • logic use across environments
  • server redundancy
  • easy updates because databases and app levels are separated
• 3-Tier Disadvantages

  • Increased complexity and configuration
  • Increased security protocols due to multiple communication/entry points
  • Expensive as more infrastructure is needed
  • Expert staff to build and maintain all layers
• ETL Process- extract, transform, load process is a process that involves the collection, transformation, and loading of data from multiple sources into a single target system

  
• Interface

  • Allows apps to work together
  • Different storing methods
  • single end point and repository
  • Allows analytics from different sources
  • HL7 standards set for input and output
  • Must be on same network
• HL7

  • International standards development
  • Clinical and Administrative data transmission
  • Communication between Patient Admin Systems (PAS), electronic practice management, lab info systems (interfaces), dietary, pharmacy (clinical decision support), billing, EHR
• HL7 Example

  • First line: Message Header (MSH)
  • New line for each HL7 segment, contains ID (EVN)
  • Each segment can have fields and components
• Data Components- Tables

  • A structure where data is stored
  • One primary key per table
  • Unique names
  • The backbone of the entire system
  • One or many tables per model
  • Relationships among tables must be defined
  • Specified # of columns but can have infinite rows
• Data Element Types

  • Autonumber- sequential # automatically assigned
  • Text- character based that can include #
  • Number- limited to # only
  • Currency- #'s with decimal and currency symbol
  • Date/Time- Dates and Times
  • Yes/No- can be true and false
  • Lookup- references from preselected values or another table
  • Attachment- imported files
  • Hyperlink- website URL
• Data Components- Queries/Views

  • Inquires to extract data
  • follow syntax dictated by language
  • data viewed in specific order
  • perform calculations
  • automation of tasks
  • SQL: code stored on client (query) and code stored on server (view)
• Data Components- Forms

  • Interface for viewing and editing data
  • Easier Data entry for end users
  • Developers can organize data differently than table structure
  • Show many fields from the table as needed
  • ability to look up values from other tables in a single form
  • can assign predefined values to a single box
  • combo box, radio buttons, single pick list
• Data Components- Reports

  • Printed output organized in any manner
  • viewable on screen
  • can be emailed or transferred to directory
  • scheduled time/day or run on demand
  • End users do not have login or access to DBMS
  • Multiple users can access same report
  • data can be group and sorted