Examples: Use OPENXML
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
The examples in this article show how OPENXML is used to create a rowset view of an XML document. For information about the syntax of OPENXML, see OPENXML (Transact-SQL). The examples show all aspects of OPENXML, but don't specify metaproperties in OPENXML. For more information about how to specify metaproperties in OPENXML, see Specify Metaproperties in OPENXML.
Examples
When retrieving the data, rowpattern is used to identify the nodes in the XML document that determine the rows. Additionally, rowpattern is expressed in the XPath pattern language that is used in the MSXML XPath implementation. For example, if the pattern ends in an element or an attribute, a row is created for each element or attribute node that is selected by rowpattern.
The flags value provides default mapping. If no ColPattern is specified in the SchemaDeclaration, the mapping specified in flags is assumed. The flags value is ignored if ColPattern is specified in SchemaDeclaration. The specified ColPattern determines the mapping, attribute-centric or element-centric, and also the behavior in dealing with overflow and unconsumed data.
A. Execute a SELECT statement with OPENXML
The XML document in this example is made up of the <Customer>, <Order>, and <OrderDetail> elements. The OPENXML statement retrieves customer information in a two-column rowset, CustomerID and ContactName, from the XML document.
First, the sp_xml_preparedocument stored procedure is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
rowpattern (/ROOT/Customer) identifies the
<Customer>nodes to process.The flags parameter value is set to 1 and indicates attribute-centric mapping. As a result, the XML attributes map to the columns in the rowset defined in SchemaDeclaration.
In SchemaDeclaration, in the WITH clause, the specified ColName values match the corresponding XML attribute names. Therefore, the ColPattern parameter isn't specified in SchemaDeclaration.
The SELECT statement then retrieves all the columns in the rowset provided by OPENXML.
DECLARE @DocHandle int;
DECLARE @XmlDocument nvarchar(1000);
SET @XmlDocument = N'<ROOT>
<Customer CustomerID="VINET" ContactName="Paul Henriot">
<Order OrderID="10248" CustomerID="VINET" EmployeeID="5"
OrderDate="1996-07-04T00:00:00">
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" ContactName="Carlos Gonzalez">
<Order OrderID="10283" CustomerID="LILAS" EmployeeID="3"
OrderDate="1996-08-16T00:00:00">
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @DocHandle OUTPUT, @XmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@DocHandle, '/ROOT/Customer',1)
WITH (CustomerID varchar(10),
ContactName varchar(20));
EXEC sp_xml_removedocument @DocHandle;
This is the result:
CustomerID ContactName
---------- --------------------
VINET Paul Henriot
LILAS Carlos Gonzalez
Because the <Customer> elements don't have any subelements, if the same SELECT statement is executed with flags set to 2 to indicate element-centric mapping, the values of CustomerID and ContactName for both the customers are returned as NULL.
The @xmlDocument can also be of xml type or of (n)varchar(max) type.
If <CustomerID> and <ContactName> in the XML document are subelements, the element-centric mapping retrieves the values.
DECLARE @XmlDocumentHandle int;
DECLARE @XmlDocument nvarchar(1000);
SET @XmlDocument = N'<ROOT>
<Customer>
<CustomerID>VINET</CustomerID>
<ContactName>Paul Henriot</ContactName>
<Order OrderID="10248" CustomerID="VINET" EmployeeID="5" OrderDate="1996-07-04T00:00:00">
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer>
<CustomerID>LILAS</CustomerID>
<ContactName>Carlos Gonzalez</ContactName>
<Order OrderID="10283" CustomerID="LILAS" EmployeeID="3" OrderDate="1996-08-16T00:00:00">
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @XmlDocumentHandle OUTPUT, @XmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@XmlDocumentHandle, '/ROOT/Customer',2)
WITH (CustomerID varchar(10),
ContactName varchar(20));
EXEC sp_xml_removedocument @XmlDocumentHandle;
This is the result:
CustomerID ContactName
---------- --------------------
VINET Paul Henriot
LILAS Carlos Gonzalez
The document handle returned by sp_xml_preparedocument is valid during the batch and not the session.
B. Specify ColPattern for mapping between rowset columns and the XML attributes and elements
This example shows how the XPath pattern is specified in the optional ColPattern parameter to provide mapping between rowset columns and the XML attributes and elements.
The XML document in this example is made up of the <Customer>, <Order>, and <OrderDetail> elements. The OPENXML statement retrieves customer and order information as a rowset (CustomerID, OrderDate, ProdID, and Qty) from the XML document.
First, the sp_xml_preparedocument stored procedure is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
- rowpattern (/ROOT/Customer/Order/OrderDetail) identifies the
<OrderDetail>nodes to process.
For illustration, the flags parameter value is set to 2 and indicates element-centric mapping. However, the mapping specified in ColPattern overwrites this mapping. That is, the XPath pattern specified in ColPattern maps the columns in the rowset to attributes. This results in attribute-centric mapping.
In SchemaDeclaration, in the WITH clause, ColPattern is also specified with the ColName and ColType parameters. The optional ColPattern is the XPath pattern specified and indicates the following:
The OrderID, CustomerID, and OrderDate columns in the rowset map to the attributes of the parent of the nodes identified by rowpattern, and rowpattern identifies the
<OrderDetail>nodes. Therefore, the CustomerID and OrderDate columns map to CustomerID and OrderDate attributes of the<Order>element.The ProdID and Qty columns in the rowset map to the ProductID and Quantity attributes of the nodes identified in rowpattern.
The SELECT statement then retrieves all the columns in the rowset provided by OPENXML.
DECLARE @XmlDocumentHandle int;
DECLARE @XmlDocument nvarchar(1000);
SET @XmlDocument = N'<ROOT>
<Customer CustomerID="VINET" ContactName="Paul Henriot">
<Order OrderID="10248" CustomerID="VINET" EmployeeID="5"
OrderDate="1996-07-04T00:00:00">
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" ContactName="Carlos Gonzalez">
<Order OrderID="10283" CustomerID="LILAS" EmployeeID="3"
OrderDate="1996-08-16T00:00:00">
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @XmlDocumentHandle OUTPUT, @XmlDocument;
-- Execute a SELECT stmt using OPENXML rowset provider.
SELECT *
FROM OPENXML (@XmlDocumentHandle, '/ROOT/Customer/Order/OrderDetail',2)
WITH (OrderID int '../@OrderID',
CustomerID varchar(10) '../@CustomerID',
OrderDate datetime '../@OrderDate',
ProdID int '@ProductID',
Qty int '@Quantity');
EXEC sp_xml_removedocument @XmlDocumentHandle;
This is the result:
OrderID CustomerID OrderDate ProdID Qty
-------------------------------------------------------------
10248 VINET 1996-07-04 00:00:00.000 11 12
10248 VINET 1996-07-04 00:00:00.000 42 10
10283 LILAS 1996-08-16 00:00:00.000 72 3
The XPath pattern specified as ColPattern can also be specified to map the XML elements to the rowset columns. This results in element-centric mapping. In the following example, the XML document <CustomerID> and <OrderDate> are subelements of the <Orders> element. Because ColPattern overwrites the mapping specified in the flags parameter, the flags parameter isn't specified in OPENXML.
DECLARE @docHandle int;
DECLARE @XmlDocument nvarchar(1000);
SET @XmlDocument = N'<ROOT>
<Customer CustomerID="VINET" ContactName="Paul Henriot">
<Order EmployeeID="5" >
<OrderID>10248</OrderID>
<CustomerID>VINET</CustomerID>
<OrderDate>1996-07-04T00:00:00</OrderDate>
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" ContactName="Carlos Gonzalez">
<Order EmployeeID="3" >
<OrderID>10283</OrderID>
<CustomerID>LILAS</CustomerID>
<OrderDate>1996-08-16T00:00:00</OrderDate>
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @XmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/ROOT/Customer/Order/OrderDetail')
WITH (CustomerID varchar(10) '../CustomerID',
OrderDate datetime '../OrderDate',
ProdID int '@ProductID',
Qty int '@Quantity');
EXEC sp_xml_removedocument @docHandle;
C. Combine attribute-centric and element-centric mapping
In this example, the flags parameter is set to 3 and indicates that both attribute-centric and element-centric mapping will be applied. In this case, the attribute-centric mapping is applied first, and then element-centric mapping is applied for all the columns not yet dealt with.
DECLARE @docHandle int;
DECLARE @XmlDocument nvarchar(1000);
SET @XmlDocument =N'<ROOT>
<Customer CustomerID="VINET" >
<ContactName>Paul Henriot</ContactName>
<Order OrderID="10248" CustomerID="VINET" EmployeeID="5"
OrderDate="1996-07-04T00:00:00">
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" >
<ContactName>Carlos Gonzalez</ContactName>
<Order OrderID="10283" CustomerID="LILAS" EmployeeID="3"
OrderDate="1996-08-16T00:00:00">
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @XmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/ROOT/Customer',3)
WITH (CustomerID varchar(10),
ContactName varchar(20));
EXEC sp_xml_removedocument @docHandle;
This is the result
CustomerID ContactName
---------- --------------------
VINET Paul Henriot
LILAS Carlos Gonzalez
The attribute-centric mapping is applied for CustomerID. There is no ContactName attribute in the <Customer> element. Therefore, element-centric mapping is applied.
D. Specify the text() XPath function as ColPattern
The XML document in this example is made up of the <Customer> and <Order> elements. The OPENXML statement retrieves a rowset that is made up of the oid attribute from the <Order> element, the ID of the parent of the node identified by rowpattern, and the leaf-value string of the element content.
First, the sp_xml_preparedocument stored procedure is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
rowpattern (/root/Customer/Order) identifies the
<Order>nodes to process.The flags parameter value is set to 1 and indicates attribute-centric mapping. As a result, the XML attributes map to the rowset columns defined in SchemaDeclaration.
In SchemaDeclaration in the WITH clause, the oid and amount rowset column names match the corresponding XML attribute names. Therefore, the ColPattern parameter isn't specified. For the comment column in the rowset, the XPath function,
text(), is specified as ColPattern. This overwrites the attribute-centric mapping specified in flags, and the column contains the leaf-value string of the element content.
The SELECT statement then retrieves all the columns in the rowset provided by OPENXML.
DECLARE @docHandle int;
DECLARE @xmlDocument nvarchar(1000);
--sample XML document
SET @xmlDocument =N'<root>
<Customer cid= "C1" name="Janine" city="Issaquah">
<Order oid="O1" date="1/20/1996" amount="3.5" />
<Order oid="O2" date="4/30/1997" amount="13.4">Customer was very satisfied
</Order>
</Customer>
<Customer cid="C2" name="Ursula" city="Oelde" >
<Order oid="O3" date="7/14/1999" amount="100" note="Wrap it blue
white red">
<Urgency>Important</Urgency>
Happy Customer.
</Order>
<Order oid="O4" date="1/20/1996" amount="10000"/>
</Customer>
</root>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @xmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/root/Customer/Order', 1)
WITH (oid char(5),
amount float,
comment ntext 'text()');
EXEC sp_xml_removedocument @docHandle;
This is the result:
oid amount comment
----- ----------- -----------------------------
O1 3.5 NULL
O2 13.4 Customer was very satisfied
O3 100.0 Happy Customer.
O4 10000.0 NULL
E. Specify TableName in the WITH clause
This example specifies TableName in the WITH clause instead of SchemaDeclaration. This is useful if you have a table that has the structure you want and no column patterns, ColPattern parameter, are required.
The XML document in this example is made up of the <Customer> and <Order> elements. The OPENXML statement retrieves order information in a three-column rowset (oid, date, and amount) from the XML document.
First, the sp_xml_preparedocument stored procedure is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
rowpattern (/root/Customer/Order) identifies the
<Order>nodes to process.There's no SchemaDeclaration in the WITH clause. Instead, a table name is specified. Therefore, the table schema is used as the rowset schema.
The flags parameter value is set to 1 and indicates attribute-centric mapping. Therefore, attributes of the elements, identified by rowpattern, map to the rowset columns with the same name.
The SELECT statement then retrieves all the columns in the rowset provided by OPENXML.
-- Create a test table. This table schema is used by OPENXML as the
-- rowset schema.
CREATE TABLE T1(oid char(5), date datetime, amount float);
GO
DECLARE @docHandle int;
DECLARE @xmlDocument nvarchar(1000);
-- Sample XML document
SET @xmlDocument =N'<root>
<Customer cid= "C1" name="Janine" city="Issaquah">
<Order oid="O1" date="1/20/1996" amount="3.5" />
<Order oid="O2" date="4/30/1997" amount="13.4">Customer was very
satisfied</Order>
</Customer>
<Customer cid="C2" name="Ursula" city="Oelde" >
<Order oid="O3" date="7/14/1999" amount="100" note="Wrap it blue
white red">
<Urgency>Important</Urgency>
</Order>
<Order oid="O4" date="1/20/1996" amount="10000"/>
</Customer>
</root>';
--Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @xmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/root/Customer/Order', 1)
WITH T1;
EXEC sp_xml_removedocument @docHandle;
This is the result:
oid date amount
----- --------------------------- ----------
O1 1996-01-20 00:00:00.000 3.5
O2 1997-04-30 00:00:00.000 13.4
O3 1999-07-14 00:00:00.000 100.0
O4 1996-01-20 00:00:00.000 10000.0
F. Obtain the result in an edge table format
In this example, the WITH clause isn't specified in the OPENXML statement. As a result, the rowset generated by OPENXML has an edge table format. The SELECT statement returns all the columns in the edge table.
The sample XML document in the example is made up of the <Customer>, <Order>, and <OrderDetail> elements.
First, the sp_xml_preparedocument stored procedure is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
rowpattern (/ROOT/Customer) identifies the
<Customer>nodes to process.The WITH clause isn't provided. Therefore, OPENXML returns the rowset in an edge table format.
The SELECT statement then retrieves all the columns in the edge table.
DECLARE @docHandle int;
DECLARE @xmlDocument nvarchar(1000);
SET @xmlDocument = N'<ROOT>
<Customer CustomerID="VINET" ContactName="Paul Henriot">
<Order CustomerID="VINET" EmployeeID="5" OrderDate=
"1996-07-04T00:00:00">
<OrderDetail OrderID="10248" ProductID="11" Quantity="12"/>
<OrderDetail OrderID="10248" ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" ContactName="Carlos Gonzalez">
<Order CustomerID="LILAS" EmployeeID="3" OrderDate=
"1996-08-16T00:00:00">
<OrderDetail OrderID="10283" ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
--Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @xmlDocument;
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/ROOT/Customer');
EXEC sp_xml_removedocument @docHandle;
The result is returned as an edge table. You can write queries against the edge table to obtain information. For example:
The following query returns the number of Customer nodes in the document. Because the WITH clause isn't specified, OPENXML returns an edge table. The SELECT statement queries the edge table.
SELECT count(*) FROM OPENXML(@docHandle, '/') WHERE localname = 'Customer';The following query returns the local names of XML nodes of element type.
SELECT distinct localname FROM OPENXML(@docHandle, '/') WHERE nodetype = 1 ORDER BY localname;
G. Specify rowpattern ending with an attribute
The XML document in this example is made up of the <Customer>, <Order>, and <OrderDetail> elements. The OPENXML statement retrieves information about the order details in a three-column rowset (ProductID, Quantity, and OrderID) from the XML document.
First, the sp_xml_preparedocument is called to obtain a document handle. This document handle is passed to OPENXML.
The OPENXML statement illustrates the following:
rowpattern (/ROOT/Customer/Order/OrderDetail/@ProductID) ends with an XML attribute, ProductID. In the resulting rowset, a row is created for each attribute node selected in the XML document.
In this example, the flags parameter isn't specified. Instead, the mappings are specified by the ColPattern parameter.
In SchemaDeclaration in the WITH clause, ColPattern is also specified with the ColName and ColType parameters. The optional ColPattern is the XPath pattern specified to indicate the following:
The XPath pattern (.) specified as ColPattern for the ProdID column in the rowset identifies the context node, current node. As per the rowpattern specified, it's the ProductID attribute of the
<OrderDetail>element.The ColPattern, ../@Quantity, specified for the Qty column in the rowset identifies the Quantity attribute of the parent,
<OrderDetail>, node of the context node, <ProductID>.Similarly, the ColPattern, ../../@OrderID, specified for the OID column in the rowset identifies the OrderID attribute of the parent,
<Order>, of the parent node of the context node. The parent node is<OrderDetail>, and the context node is<ProductID>.
The SELECT statement then retrieves all the columns in the rowset provided by OPENXML.
DECLARE @docHandle int;
DECLARE @xmlDocument nvarchar(1000);
--Sample XML document
SET @xmlDocument =N'<ROOT>
<Customer CustomerID="VINET" ContactName="Paul Henriot">
<Order OrderID="10248" CustomerID="VINET" EmployeeID="5" OrderDate=
"1996-07-04T00:00:00">
<OrderDetail ProductID="11" Quantity="12"/>
<OrderDetail ProductID="42" Quantity="10"/>
</Order>
</Customer>
<Customer CustomerID="LILAS" ContactName="Carlos Gonzalez">
<Order OrderID="10283" CustomerID="LILAS" EmployeeID="3" OrderDate=
"1996-08-16T00:00:00">
<OrderDetail ProductID="72" Quantity="3"/>
</Order>
</Customer>
</ROOT>';
-- Create an internal representation of the XML document.
EXEC sp_xml_preparedocument @docHandle OUTPUT, @xmlDocument
-- Execute a SELECT statement using OPENXML rowset provider.
SELECT *
FROM OPENXML (@docHandle, '/ROOT/Customer/Order/OrderDetail/@ProductID')
WITH ( ProdID int '.',
Qty int '../@Quantity',
OID int '../../@OrderID');
EXEC sp_xml_removedocument @docHandle;
This is the result:
ProdID Qty OID
----------- ----------- -------
11 12 10248
42 10 10248
72 3 10283
H. Specify an XML document that has multiple text nodes
If you have multiple text nodes in an XML document, a SELECT statement with a ColPattern, text(), returns only the first text node, instead of all of them. For example:
DECLARE @h int;
EXEC sp_xml_preparedocument @h OUTPUT,
N'<root xmlns:a="urn:1">
<a:Elem abar="asdf">
T<a>a</a>U
</a:Elem>
</root>',
'<ns xmlns:b="urn:1" />';
SELECT * FROM openxml(@h, '/root/b:Elem')
WITH (Col1 varchar(20) 'text()');
EXEC sp_xml_removedocument @h;
The SELECT statement returns T as the result, and not TaU.
I. Specify the XML data type in the WITH clause
In the WITH clause, a column pattern that is mapped to the xml data type column, whether typed or untyped, must return either an empty sequence or a sequence of elements, processing instructions, text nodes, and comments. The data is cast to an xml data type.
In the following example, the table schema declaration in the WITH clause includes xml type columns.
DECLARE @h int;
DECLARE @x xml;
set @x = '<Root>
<row id="1"><lname>Duffy</lname>
<Address>
<Street>111 Maple</Street>
<City>Seattle</City>
</Address>
</row>
<row id="2"><lname>Wang</lname>
<Address>
<Street>222 Pine</Street>
<City>Bothell</City>
</Address>
</row>
</Root>';
EXEC sp_xml_preparedocument @h output, @x;
SELECT *
FROM OPENXML (@h, '/Root/row', 10)
WITH (id int '@id',
lname varchar(30),
xmlname xml 'lname',
OverFlow xml '@mp:xmltext');
EXEC sp_xml_removedocument @h;
Specifically, you're passing an xml type variable (@x) to the sp_xml_preparedocument() function.
This is the result:
id lname xmlname OverFlow
--- ------- ------------------------------ -------------------------------
1 Duffy <lname>Duffy</lname> <row><Address>
<Street>111 Maple</Street>
<City>Seattle</City>
</Address></row>
2 Wang <lname>Wang</lname> <row><Address>
<Street>222 Pine</Street>
<City>Bothell</City>
</Address></row>
Note the following from the result:
For the lname column of varchar(30) type, its value is retrieved from the corresponding
<lname>element.For the xmlname column of xml type, the same name element is returned as its value.
The flag is set to 10. The 10 means 2 + 8, where 2 indicates element-centric mapping and 8 indicates that only unconsumed XML data should be added to the OverFlow column defined in the WITH clause. If you set the flag to 2, the whole XML document is copied to the OverFlow column that is specified in the WITH clause.
In case the column in the WITH clause is a typed XML column and the XML instance doesn't confirm to the schema, an error is returned.
J. Retrieve individual values from multivalued attributes
An XML document can have attributes that are multivalued. For example, the IDREFS attribute can be multivalued. In an XML document, the multivalued attribute values are specified as a string, with the values separated by a space. In the following XML document, the attends attribute of the <Student> element and the attendedBy attribute of <Class> are multivalued. Retrieving individual values from a multivalued XML attribute and storing each value in a separate row in the database requires extra work. This example shows the process.
This sample XML document is made up of the following elements:
<Student>
The id (student ID), name, and attends attributes. The attends attribute is a multivalued attribute.
<Class>
The id (class ID), name, and attendedBy attributes. The attendedBy attribute is a multivalued attribute.
The attends attribute in <Student> and the attendedBy attribute in <Class> represent a m:n relationship between the Student and Class tables. A student can take many classes and a class can have many students.
Assume that you want to shred this document and save it in the database as shown in the following:
Save the
<Student>data in the Students table.Save the
<Class>data in the Courses table.Save the m:n relationship data, between Student and Class, in the CourseAttendence table. More work is required to extract the values. To retrieve this information and store it in the table, use these stored procedures:
Insert_Idrefs_Values
Inserts the values of course ID and student ID in the CourseAttendence table.
Extract_idrefs_values
Extracts the individual student IDs from each <Course> element. An edge table is used to retrieve these values.
Here are the steps:
-- Create these tables:
DROP TABLE CourseAttendance;
DROP TABLE Students;
DROP TABLE Courses;
GO
CREATE TABLE Students(
id varchar(5) primary key,
name varchar(30)
);
GO
CREATE TABLE Courses(
id varchar(5) primary key,
name varchar(30),
taughtBy varchar(5)
);
GO
CREATE TABLE CourseAttendance(
id varchar(5) references Courses(id),
attendedBy varchar(5) references Students(id),
constraint CourseAttendance_PK primary key (id, attendedBy)
);
GO
-- Create these stored procedures:
DROP PROCEDURE f_idrefs;
GO
CREATE PROCEDURE f_idrefs
@t varchar(500),
@idtab varchar(50),
@id varchar(5)
AS
DECLARE @sp int;
DECLARE @att varchar(5);
SET @sp = 0;
WHILE (LEN(@t) > 0)
BEGIN
SET @sp = CHARINDEX(' ', @t+ ' ');
SET @att = LEFT(@t, @sp-1);
EXEC('INSERT INTO '+@idtab+' VALUES ('''+@id+''', '''+@att+''')');
SET @t = SUBSTRING(@t+ ' ', @sp+1, LEN(@t)+1-@sp);
END;
GO
DROP PROCEDURE fill_idrefs
GO
CREATE PROCEDURE fill_idrefs
@xmldoc int,
@xpath varchar(100),
@from varchar(50),
@to varchar(50),
@idtable varchar(100)
AS
DECLARE @t varchar(500);
DECLARE @id varchar(5);
/* Temporary Edge table */
SELECT *
INTO #TempEdge
FROM OPENXML(@xmldoc, @xpath);
DECLARE fillidrefs_cursor CURSOR FOR
SELECT CAST(iv.text AS nvarchar(200)) AS id,
CAST(av.text AS nvarchar(4000)) AS refs
FROM #TempEdge c, #TempEdge i,
#TempEdge iv, #TempEdge a, #TempEdge av
WHERE c.id = i.parentid
AND UPPER(i.localname) = UPPER(@from)
AND i.id = iv.parentid
AND c.id = a.parentid
AND UPPER(a.localname) = UPPER(@to)
AND a.id = av.parentid;
OPEN fillidrefs_cursor
FETCH NEXT FROM fillidrefs_cursor INTO @id, @t;
WHILE (@@FETCH_STATUS <> -1)
BEGIN
IF (@@FETCH_STATUS <> -2)
BEGIN
execute f_idrefs @t, @idtable, @id;
END
FETCH NEXT FROM fillidrefs_cursor INTO @id, @t
END;
CLOSE fillidrefs_cursor;
DEALLOCATE fillidrefs_cursor;
Go
-- This is the sample document that is shredded and the data is stored in the preceding tables.
DECLARE @h int;
EXECUTE sp_xml_preparedocument @h OUTPUT, N'<Data>
<Student id = "s1" name = "Student1" attends = "c1 c3 c6" />
<Student id = "s2" name = "Student2" attends = "c2 c4" />
<Student id = "s3" name = "Student3" attends = "c2 c4 c6" />
<Student id = "s4" name = "Student4" attends = "c1 c3 c5" />
<Student id = "s5" name = "Student5" attends = "c1 c3 c5 c6" />
<Student id = "s6" name = "Student6" />
<Class id = "c1" name = "Intro to Programming"
attendedBy = "s1 s4 s5" />
<Class id = "c2" name = "Databases"
attendedBy = "s2 s3" />
<Class id = "c3" name = "Operating Systems"
attendedBy = "s1 s4 s5" />
<Class id = "c4" name = "Networks" attendedBy = "s2 s3" />
<Class id = "c5" name = "Algorithms and Graphs"
attendedBy = "s4 s5"/>
<Class id = "c6" name = "Power and Pragmatism"
attendedBy = "s1 s3 s5" />
</Data>';
INSERT INTO Students SELECT * FROM OPENXML(@h, '//Student') WITH Students
INSERT INTO Courses SELECT * FROM OPENXML(@h, '//Class') WITH Courses
/* Using the edge table */
EXECUTE fill_idrefs @h, '//Class', 'id', 'attendedby', 'CourseAttendance';
SELECT * FROM Students;
SELECT * FROM Courses;
SELECT * FROM CourseAttendance;
EXECUTE sp_xml_removedocument @h;
K. Retrieve binary from base64 encoded data in XML
Binary data is frequently included in XML using base64 encoding. When you shred this XML by using OPENXML, you receive the base64 encoded data. This example shows how you can convert the base64 encoded data back to binary.
Create a table with sample binary data.
Use a FOR XML query and the BINARY BASE64 option to construct XML that has the binary data encoded as base64.
Shred the XML by using OPENXML. The data returned by OPENXML will be base64 encoded data. Next, call the
.valuefunction to convert it back to binary.
CREATE TABLE T (Col1 int primary key, Col2 varbinary(100));
GO
-- Insert sample binary data
INSERT T VALUES(1, 0x1234567890);
GO
-- Create test XML document that has base64 encoded binary data (use FOR XML query and specify BINARY BASE64 option)
SELECT * FROM T
FOR XML AUTO, BINARY BASE64;
GO
-- result
-- <T Col1="1" Col2="EjRWeJA="/>
-- Now shredd the sample XML using OPENXML.
-- Call the .value function to convert
-- the base64 encoded data returned by OPENXML to binary.
DECLARE @h int;
EXEC sp_xml_preparedocument @h OUTPUT, '<T Col1="1" Col2="EjRWeJA="/>';
SELECT Col1,
CAST('<binary>' + Col2 + '</binary>' AS XML).value('.', 'varbinary(max)') AS BinaryCol
FROM openxml(@h, '/T')
WITH (Col1 integer, Col2 varchar(max)) ;
EXEC sp_xml_removedocument @h;
GO
This is the result. The binary data returned is the original binary data in table T.
Col1 BinaryCol
----------- ---------------------
1 0x1234567890