DEV-5: Using ProDataSets

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DEV-5 Using ProDataSetsin OpenEdge 10
Cheryl LaBarge
Product Readiness
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Agenda
ProDataSets

• Evolution of data access
• Reasons to use ProDataSets
• Sharing data easily with the outside world
• Where to go next

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Evolution of Data Access
Combining the best of the past to meet the
demands of the future
SDO
ProDataSet
Temp-Tables
 
 
 
 
 
 
 
XML
Temp-Tables
 
 
 
 
 
 
 
ProDataSet
Temp-Tables
 
 
 
 
 
 
 
Flexibility
Temp-Tables
 
 
 
 
 
 
 
.NET
Temp-Tables
 
 
 
 
 
 
 
Temp-Tables
 
 
 
 
 
 
 
Java
Temp-Tables
 
 
 
 
 
 
 
Work File
 
 
 
 
 
 
 
.db
.dbi
Web SOA Beyond
Client Server
Host Centric
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Agenda
ProDataSets

• Evolution of data access
• Reasons to use ProDataSets
• Sharing data easily with the outside world
• Where to go next

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Reasons to Use ProDataSets
Complex multilevel data structures as a single
entity

• Strength of temporary tables
• Flexibility to group data for business needs
• Straight forward methods and events
• Data caching
• Batching

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The Strength of the Temporary Table
Based on the familiar temporary table
Color code text
Outline view
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Temporary Tables Available for Use in UI
AppBuilder perspective uses temp-tables for
building a browse
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Reasons to Use ProDataSets
Complex multilevel data structures as a single
entity

• Strength of temporary tables
• Flexibility to group data for business needs
• Straight forward methods and events
• Data caching
• Batching

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Flexibility to Group Data for Business Needs

• The DATA-RELATION (OrderLine) defines the
  relationship between parent-child tables

• The RELATION-FIELDS (OrderNum, OrderNum) define
  fields in parent and child to use for selection
• Defaults for
• Populating
• Navigating

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Data-Sources Easy to Use

• The Data-Source is a separate object from the
  ProDataSet
• One for each temp-table buffer
• Can define database buffers or a query or both
• XML methods allow easy loading of data from
  external sources

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Relating the ProDataSet
Using relation fields to define foreign keys
Related Order lines
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Data-Sources Provide Data Flexibility
The Data-Source can be more complex

• Data-Source can flatten a triple join into a
  single table

Related Order lines
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Ability to Modify the Query

• Because they are based on temp-tables it is easy
  to use familiar QUERY-PREPARE to select necessary
  records

Top level ONLY!
Child fills based on data source and relation
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Reasons to Use ProDataSets
Complex multilevel data structures as a single
entity

• Strength of temporary tables
• Flexibility to group data for business needs
• Straight forward methods and events
• Data caching
• Batching

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Filling a ProDataSet
Straight forward FILL method

• Populate the ProDataSet from the Data-Sources
• FILL on the DataSet
• Fills every table starting with top-level buffers
• FILL on a buffer
• Fills that table and its descendents
• FILL-MODE on each buffer
• NO-FILL skip this table
• EMPTY empty the table first
• APPEND add more records to the table
• MERGE add records eliminate duplicates
• REPLACE replace existing records

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Populating with Data-Relations
Navigate.w

• When a DataSet is populated, OpenEdge retrieves
  children of the current parent

ProDataSet
Order Data-Source
Application Database
Data-Relation
ttOLine
6 1 000096 2 000096 3 00011
OrderLine Data-Source
84 1 0000984 2 0000984 3 00011
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Event Callback Procedures

• You can define event procedures for
• Before and After FILL of the ProDataSet
• Before and After FILL of any temp-table buffer
• Before and After FILL of any record
• Use ProDataSet events to prepare queries, attach
  Data-Sources, etc.
• Use Buffer events to manipulate the table
• Use Record events to populate calculated fields
• You can use these events when there is no
  Data-Source at all

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Setting Callback Events
Advantage over .NET dataset is the buffer storing
current record context (ttOrder)
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Navigating
dsOrderWinUp.w

1. Browse functionality

1. Query syntax

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Updating Through the ProDataSet
Defining a BEFORE-TABLE

• ProDataSet tables can have a companion
  before-image temp-table to record updates
  (add/change/delete)
• Used to pass changes to the server to be made in
  the Data-Source and error messages to the client
• Maps to .NET and Java support for update versions

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Before-Image Table for a DataSet
dsOrderWinUp.w - Original record Values for order
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Delete Lines 2, 4, 5 Modify Line 1 to have
60 Add 60 Fishing Lures (Item 44) Add 30 Fishing
Poles (Item 13)
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Before-Image Table for a DataSet
ProDataSet/dsCompareTables.w

• Select

ROW-DELETED ROW-MODIFIED ROW-CREATED
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Saving Changes to the Database

• SAVE-ROW-CHANGES method for saving a row to the
  database
• Uses the before-table for optimistic locking
• Allows full control in the event of a conflict
• ERROR, ERROR-STRING, REJECTED, DATA-SOURCE-MODIFIE
  D attributes

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ProDataSet Demo
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Reasons to Use ProDataSets
Complex multilevel data structures as a single
entity

• Strength of temporary tables
• Flexibility to group data for business needs
• Straight forward methods and events
• Data caching
• Batching

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Data Caching
Passing a ProDataSet as a Parameter

• DATASET static reference like TABLE
• DATASET-HANDLE dynamic reference to the DataSet
  and its definition, like TABLE-HANDLE passes a
  simple DataSet handle to a local procedure
• Note!
• By default the DATASET and DATASET-HANDLE
  parameters copy the ProDataSet contents (deep
  copy)

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Passing a ProDataSet BY-REFERENCELocal to a
Single Session
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Remote DataSet Parameter BY-REFERENCE
BY-REFERENCE is ignored, always a deep copy
AppServer
ProDataSet
ProDataSet
Deep Copy
Temp-Tables
 
 
 
 
 
 
 
Temp-Tables
 
 
 
 
 
 
 
Temp-Tables
 
 
 
 
 
 
 
Temp-Tables
 
 
 
 
 
 
 
Client
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Illustration of BY-REFERENCE Local Call
Please note example was coded without this option
ProDataSet
Unused ProDataSet
Order
 
Order
 
Olines
 
 
 
DEFINE DATASET dsRef
DEFINE DATASET dsOrder REFERENCE-ONLY.
Olines
 
 
 
dsOrderFILL().
PROCEDURE FillWithWhere DEFINE INPUT icWhere AS
CHARACTER NO-UNDO. DEFINE OUTPUT PARAMETER FOR
DATASET dsOrder. dsOrderFILL(). END PROCEDURE.
RUN FillWithWHERE IN hOrderMain (INPUT icWhere,
OUTPUT DATASET dsRef BY-REFERENCE).

• Always the callers instance used
• Called procedure instantiates a ProDataSet that
  is never used
• References are redirected for the duration of
  that procedure call only

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Options for Parameters Local CallFor Data
Caching
PriceListDataCache.p
ProDataSet
ItemSelection.p
Unused ProDataSet
Pricelist







Pricelist






Define DATASET dsPrices REFERENCE-ONLY
Define DATASET dsRef
PROCEDURE bindData DEFINE OUTPUT PARAMETER FOR
DATASET dsRef BIND. END PROCEDURE.
RUN bindData IN hProc2 (OUTPUT DATASET dsPrices
BIND)
RUN fetchData IN hProc2. DISPLAY ltdsPrices
fieldsgt.
PROCEDURE fetchData dsRefFILL().

• ProDataSet or temp-table on one side of the
  call is defined REFERENCE-ONLY
• Use the BIND option on both sides of a single
  procedure call
• No need to pass the ProDataSet again!

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Summary of BY-REFERENCE and BIND

• BY-REFERENCE
• To use the callers ProDataSet instance in the
  called procedure
• REFERENCE-ONLY
• For the unused instance
• BIND
• To identify called or caller procedures instance
  to use
• Useful for data caching and separation of data
  management from user interface

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Reasons to Use ProDataSets
Complex multilevel data structures as a single
entity

• Strength of temporary tables
• Flexibility to group data for business needs
• Straight forward methods and events
• Data caching
• Batching

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Batching in a Distributed Stateless Environment
AppServer
Client
Database
dsCustomer
eCustomer




dsCustomer
eCustomer








BATCH-SIZE
QUERY CustBrowse
LAST-BATCH
OFF-END event
PROCEDURE offEnd
NEXT-ROWID
Procedure fetchWhere DATASET dsCustomerFILL()
PROCEDURE fetchCustomers RUN fetchWhere ON
hAppServer (OUTPUT DATASET dsCustomer)

RESTART-ROWID
APPEND)
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ProDataSet Events to Support Data Batching

• The goal is to make data retrieval with batching
  transparent
• OFF-END event for a ProDataSet query
• Occurs when a query goes off the end
• Occurs before BrowseOFF-END
• Occurs before QueryQUERY-OFF-END
• FIND-FAILED for a FIND on a buffer
• Use to respond to individual missing rows

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Sample Code for Batching

• Set up an event handler for OFF-END

QUERY CustBrowseSET-CALLBACK(OFF-END,
OffEnd).

• Define the event handler

PROCEDURE OffEnd DEFINE INPUT PARAMETER
DATASET FOR dsCustomer. IF NOT BUFFER
eCustomerLAST-BATCH THEN DO RUN
fetchCustomers. RETURN NO-APPLY. / Cancel
OFF-END / END. END PROCEDURE.
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Requesting a Batch from the Server

• Make the request

RUN fetchWhere ON hServer (INPUT Customer,
INPUT iBatchSize, INPUT-OUTPUT rRestartRowid,
INPUT cWhereString, OUTPUT DATASET
dsCustomer APPEND).

• Handle the request for data on the server

hCustBufferBATCH-SIZE iBatchSize.
hDataSourceRESTART-ROWID(1) rRestartRowid.
hCustQueryQUERY-PREPARE(FOR EACH Customer WHERE
cWhereString). DATASET dsCustomerFILL(). IF
hCustBufferLAST-BATCH NO THEN rRestartRowid
hDataSourceNEXT-ROWID(1).
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Agenda
ProDataSets

• Evolution of data access
• Reasons to use ProDataSets
• Sharing data easily with the outside world
• Where to go next

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Converting Between XML and ProDataSets

• Exporting the entire ProDataSet to XML
• WRITE-XML creates XML stream from data
• WRITE-XMLSCHEMA creates XML Schema information
  based on the data definition
• READ-XML takes XML source and loads it into a
  ProDataSet
• It can create the ProDataSet definition after a
  CREATE DATASET statement
• READ-XMLSCHEMA creates or verifies XML Schema
  information

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Ability to Add External Data
Pulling in third party items from XML based
documents
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Agenda
ProDataSets

• Evolution of data access
• Reasons to use ProDataSets
• Sharing data easily with the outside world
• Where to go next

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Relevant Exchange Sessions
Day Time Session Title
Wed. 800 -930 AM DEV-14 Using ProDataSets and WebClient for Robust B2B Applications
Wed. 1000 -1100 AM DEV-15 Building a resilient Retail System using WebClient, SonicMQ, and ProDataSets
Wed. 1000 -1100 AM DEV-16 ABL Database Objects Updated
Wed. 330-5 INT-12 Mastering ProDataSets and Native XML Datatypes with Sonic ESB
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For More Information, Go to

• PSDN
• AutoEdge Application
• Application Architecture Made Simple
• Progress eLearning Community
• Using ProDataSets
• Documentation
• 10.1B ProDataSet Manual, by John Sadd

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In Summary

• Leverages what you know
• Flexible and easy to use
• Allows applications to combine data more
  effectively to meet business needs

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Questions?
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Thank you foryour time
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