0f2858fb37
git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@5035 8e941d3f-bd1b-0410-a28a-d453659cc2b4
105 lines
3.4 KiB
Plaintext
105 lines
3.4 KiB
Plaintext
This demo shows how a TVpFlexDatastore can link to an Access database using
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ODBC.
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Step-by-step instructions for creating a new application
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--------------------------------------------------------
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- If a suitable Access database is not available from somewhere else
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create an empty Access database containing the VisualPlanit tables and fields.
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The easiest way to do this is by means of the CreateAccessDB application in
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the folder "tools". Use extension .mdb to create an old Access 97/2000 file,
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or use extension .accdb for a new Access 2007+ file.
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- Create a new form.
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- Add a TVpFlexDatastore, a TVpControlLink and the visual planner components
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needed.
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- Add an TODBConnection. Add a TSQLTransationSet
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- Set these properties of the ODBCConnection:
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- "Driver" ---> "Microsoft Access Driver (*.mdb, *.accdb)"
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- "Params" ---> Add "DBQ=full/path/to/access/file"
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Note: Make sure to use the full path in Params, otherwise the fieldmapper
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in one of the next steps will not find the database.
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- "Transaction --> instance of the SQLTransaction.
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- Add four TSQLQuery components and set these properties
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- "Database" ---> instance of the ODBCConnection
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- "Options" --> add sqoAutoApplyUpdates, sqoAutoCommit and sqoKeepOpenOnCommit
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- "UsePrimaryKeyAsKey" --> false (VERY IMPORTANT FOR ACCESS FILES!)
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- Enter these SQL for the queries where <tablename> must be replaced by
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Resources, Contacts, Events and Tasks.
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SELECT * FROM <tablename>
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- For the Resources query add this UpdateSQL:
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UPDATE
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Resources
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SET
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Description = :Description,
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Notes = :Notes,
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ResourceActive = :ResourceActive,
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ImageIndex = :ImageIndex
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WHERE
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ResourceID = :ResourceID
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- Similarly, add UpdateSQL instructions for the Events, Contacts, and Tasks tables.
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Make sure to include all database fields (except for the AutoInc fields).
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See the demo application.
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- Add this text to the DeleteSQL property of the Resources SQLDataset
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DELETE * FROM Resources
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WHERE ResourceID = :ResourceID.
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- This is the DeleteSQL needed for the Events dataset:
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DELETE * FROM Events
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WHERE RecordID = :RecordID
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- Repeat accordingly with the Contacts and Rasks datasets.
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- Add four TDatasource components. Link each one of them to a TSQLDataset.
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- Link the datasource components to the matching Datasources of the
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VpFlexDatastore.
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- In OnCreate of the form set
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VpFlexDatastore.Connected := true
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ODBConnection.Connected := true
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SQLTransaction.Active := true
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- In OnDestroy set
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ODBCConnection.Connected := false
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- Double-click on the VpFlexDatastore in Form1 to open the field mapper.
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- Select "Resources" in the combobox. Click a database field in the left listbox
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and click its corresponding planner field in the right listbox. Click add to
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store this mapping. Repeat with all database fields.
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- Or, if all database fields have the same name as the corresponding planner
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fields, simply click "Add all" to establish a mapping for all equally names
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fields.
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- Note: the sample database does not support the User-defined fields of the
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planner. Therefore, these fields will be left without a matching database
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field.
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- Repeat with the Events, Contacts and Tasks tables.
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- Close the field mapper.
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- After the field mappings have been established the absolute database path can
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be removed from the Params of the ODBCConnection and replaced by a relative
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path or can be set at runtime.
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- Done.
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