Saving Recordsets as XML
SECTION 12 Databases
196
modifications to data in a connection, regardless of the Recordset. A
transaction is started by calling DBExecute with the 'BeginTrans' command.
From that point, any request to add, modify or delete records are stored
instead of being immediately processed. The Transaction is completed either
by calling DBExecute with the 'CommitTrans' command, which processes all
the stored requests in one go, or by calling DBExecute with the
'RollbackTrans' command, which discards all the stored requests leaving the
database as it was when the Transaction started.
12-7-1 Nested Transactions
Transactions may be nested, that is a new transaction may be started before
the preceding transaction has been completed. In this case, any
'CommitTrans' or 'RollbackTrans' commands relate to the most recently
started transaction, and any further 'CommitTrans or 'RollbackTrans'
commands relate to the transaction begun before it.
12-8
Saving Recordsets as XML
Using the DBExecute() 'Save' command any Recordset may be saved as an
XML file, to be imported in to another application. XML resembles and
complements HTML. XML describes data, such as city name, temperature
and barometric pressure, and HTML defines tags that describe how the data
should be displayed, such as with a bulleted list or a table. XML, however,
allows developers to define an unlimited set of tags, bringing great flexibility to
authors, who can decide which data to use and determine its appropriate
standard or custom tags.
Example: XML is used to describe an Employees phone list:
<EmployeeList>
<Entry>
<Employee>John Jones</Employee>
<Phone>555-1213</Phone>
<Type>Mobile</Type>
</Entry>
<Entry>
<Employee>Sally Mae</Employee>
<Phone>555-1217</Phone>
<Type>Business Fax</Type>
</Entry>
</EmployeeList>
You can use an application with a built in XML parser, such as Microsoft®
Internet Explorer 5 to view XML documents in the browser just as you would
view HTML pages.
Note:
Care should be taken to ensure that each 'BeginTrans' is matched with a
'CommitTrans' or 'RollbackTrans' to ensure that your work is saved or
discarded as required. If there are any pending transactions when a
connection is closed, the user will be prompted to either commit or rollback
these outstanding transactions. A DBExecute command 'TransCount' is
available which returns the number of pending transactions.
Note:
Not all Providers support use of Transactions.
Summary of Contents for CX-Supervisor
Page 1: ...CX Supervisor Software Cat No W10E EN 01 User Manual Software Release 3 1...
Page 3: ...Copyright Notice 2...
Page 16: ...15...
Page 17: ...16...
Page 27: ...Tip of the Day SECTION 1 Graphics Editor 26...
Page 35: ...CX Supervisor Preferences SECTION 2 Pages 34...
Page 79: ...Responding to Events SECTION 5 ActiveX Objects 78...
Page 115: ...Printing the Graphics Library SECTION 7 Graphics Library 114...
Page 181: ...Data Logging SECTION 11 Data Logging 180...
Page 201: ...Examples SECTION 12 Databases 200...
Page 243: ...Performance Monitor SECTION 16 Application Analysis Performance Monitor 242...
Page 253: ...Using with Omron s CX Server OPC SECTION 17 Using CX Supervisor as an OPC Cli 252...
Page 259: ...Creating a CX Supervisor Client application SECTION 18 Connecting to a remote CX 258...
Page 263: ...Adding a Point Linked to a Parameter SECTION 19 Connecting to Omron Industrial 262...
Page 271: ...Data Logging SECTION 20 Best Practices 270...
Page 275: ...Configuring a Server PC running Windows NT or 2000 Appendix A Configuring a PC 274...
Page 277: ...Appendix B Frequently Asked Questions 276...
Page 296: ...Appendix B Frequently Asked Questions 295...
Page 297: ...Appendix B Frequently Asked Questions 296...
Page 298: ...Appendix B Frequently Asked Questions 297...
Page 299: ...Appendix B Frequently Asked Questions 298...
Page 333: ...Revision history 332...