Writing Perform Documents
EPCC, University of Edinburgh
Amy Krause
a.krause@epcc.ed.ac.uk
OGSA-DAI Training Workshop - April 2003
Release: P2R2
Talk Outline
Writing GDS perform documents
4General structure of perform documents
4Database statements:
–
–
–
–
–
SQL queries and updates
Relational Database Management
XPath queries
XUpdate statements
XML:DB Collection Management
4Delivery
4Execute and Terminate
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Structure
4Interface to GDS is documentbased
4GridDataService::perform takes an
XML document as input parameter
4GDS perform document allow the
user to specify operations/activities
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Content
GDS Perform document can contain:
4Named request element: contains the activities
AND
4Named execute element: asks to execute a
named request
OR
4terminate element: asks to terminate a named
execute request
BUT NOT request without execute
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Example
<gridDataServicePerform
xmlns="http://ogsadai.org.uk/P2R2/schemas/gds">
<request name="requestsynch">
<documentation>
<!-- human readable documentation -->
</documentation>
<parameter name="textParameter“/>
<!-- query statement -->
<sqlQueryStatement name="statement"> . . .
<!-- delivery instructions -->
<deliverToResponse name="d1"> . . .
</request>
<execute name="execute1" requestName="requestsynch">
<withParametername="textParameter">20</withParameter>
</execute>
</gridDataServicePerform>
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Perform Documents
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Request
Request
Execute
Execute
Terminate
Terminate
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Requests
Can contain
4Parameter Definitions/Declarations
4Database Query Statement
4Database Update Statement
4Database Management Statement
4Delivery Statement
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Requests
Request - Update
Request - Query
Delivery
data
Para
meter
Para
meter
data
data
Query
8
Para
meter
Para
meter
data
Para
meter
data
Para
meter
data
Update
data
data
Delivery
Delivery
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Parameters
4Currently only supported within JDBC query /
update activities
– sqlQueryStatement
– sqlUpdateStatement
4Parameter activity can define a default value
4Values can be (re-)defined within an execute
element
4Or can be streamed in from a delivery
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Parameter Activity
4Parameter activities have one output stream
4Using the name of the value element, this
output is referenced by other activities
4Optional: value contains a default value
<parameter name="textParameter">
<value name="datatoinsert">10</value>
</parameter>
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Using Parameters
4 sqlParameter references the output stream of another
activity
– output from a parameter definition
– or output from delivery
4 references the position of an SQL parameter
<sqlUpdateStatement name="statement">
<sqlParameter position="1" from="datatoinsert"/>
<dataResource>dr1</dataResource>
<expression>
insert into myimages values ?
</expression>
</sqlUpdateStatement>
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Using Parameters
4Parameter values can be overwritten within
execute statements
4The withParameter element references the
parameter name
<execute name="execute1"
requestName="request1">
<withParameter name="textParameter">
myimages
</withParameter>
</execute>
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Other Supported Activities
4Relational Type Activities:
–
–
–
–
sqlQueryStatement
sqlUpdateStatement
sqlStoredProcedure
relationalResourceManagement
4XML Type Activities:
–
–
–
–
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xPathStatement
xUpdateStatement
xmlCollectionManagement
xmlResourceManagement
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Example:
sqlQueryStatement
<sqlQueryStatement name="statement">
<dataResource>
SQLQueryStatementResource
</dataResource>
<expression>
select * from largedata where
datagroup = 10
</expression>
<webRowSetStream name="statementresult"/>
</sqlQueryStatement>
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sqlQueryStatment
with Parameters
<parameter name="textParameter">
<value name=“tablename">largedata</value>
</parameter>
<sqlQueryStatement name="statement">
<sqlParameter position="1" from=“tablename"/>
<dataResource>SQLQueryStatementResource
</dataResource>
<expression>
select * from ? where datagroup = 10
</expression>
<webRowSetStream name="statementresult" />
</sqlQueryStatement>
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Example:
xPathStatement
<xPathStatement name="statement">
<dataResource>
myXMLDBDataResource
</dataResource>
<expression>
/entry[@id&lt;100]
</expression>
<sequenceStream name="statementresult"/>
</xPathStatement>
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XML:DB Collection
Management
<xmlCollectionManagement name="statement">
<dataResource>
myXMLDBDataResource
</dataResource>
<createCollection name="musicians"/>
<createCollection name="writers"/>
<sequenceStream name="statementOutput"/>
</xmlCollectionManagement>
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Delivery
Synchronous delivery
4toResponse
Asynchronous delivery
4toURL / fromURL: ftp, http, https, file
4toGFTP / fromGFTP: by GridFTP
4toGDT / fromGDT: GridDataTransport portType
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Delivery Structure
Delivery - Push
4Input Stream: fromLocal – references the
name of another activity
4Output Stream: toURL, toGFTP, toGDT –
where to push the data to
Delivery – Pull
4Input Stream: fromURL, fromGFTP, fromGDT
– where to pull the data from
4OutputStream: fromLocal – references the
name of another activity
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Example Query with
Synchronous Delivery
<request name="myRequest">
<xPathStatement name="statement">
<dataResource>dr1</dataResource>
<expression>/entry[@id&lt;100]</expression>
<sequenceStream name="statementOutput"/>
</xPathStatement>
<deliverToResponse name="d1">
<fromLocal from="statementOutput" />
</deliverToResponse>
</request>
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Example Query with
Asynchronous Delivery to URL
<request name="myRequest">
<xPathStatement name="statement">
<dataResource>dr1</dataResource>
<expression>/entry[@id&lt;100]</expression>
<sequenceStream name="statementOutput"/>
</xPathStatement>
<deliverToURL name="d1">
<fromLocal from="statementOutput" />
<toURL>
ftp://ogsadai.org.uk/resultsets/newresultset.txt
</toURL>
</deliverToURL>
</request>
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Example Query with
Asynchronous Delivery to URL
<request name="myRequest">
<xPathStatement name="statement">
<dataResource>dr1</dataResource>
<expression>/entry[@id&lt;100]</expression>
<sequenceStream name="statementOutput"/>
</xPathStatement>
<deliverToURL name="d1">
<fromLocal from="statementOutput" />
<toURL>
file://c:/ogsadai/resultsets/newresultset.txt
</toURL>
</deliverToURL>
</request>
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Execute
4References the name of a request in the
requestName attribute
<execute name="execute1" requestName="request1"/>
4Can contain a parameter value
<execute name="execute1" requestName="request1">
<withParameter name="tablename">
myimages
</withParameter>
</execute>
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Terminate
4Terminates a running request
4References the name of an execute element
<terminate name="terminate1"
executeName="execute1">
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Exercises
4A GridDataServiceRegistry is running on
http://?????????/ogsa/services/ogsadai/
GridDataServiceRegistry
4MySQL Database: myDataResource
4Xindice Database: myXMLDataResource
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