This means you can associate an XML schema collection with the xml type column. All the instances stored in the column are validated and typed against the schema in the collection and provide the type information for XQuery. Is this page helpful? Yes No. Any additional feedback? Skip Submit. Explains the support for the xml data type in the Database Engine and the methods you can use against this data type.
Describes how the XML instances stored in a database can be typed. Provides a basic overview of XQuery concepts, and also the expression evaluation static and dynamic context , atomization, effective Boolean value, XQuery type system, sequence type matching, and error handling. XQuery Expressions. Describes XQuery primary expressions, path expressions, sequence expressions, arithmetic comparison and logical expressions, XQuery construction, FLWOR expression, conditional and quantified expressions, and various expressions on sequence types.
Modules and Prologs XQuery. Indeed, on the off chance that we take that entire statement inside the inner Query with the table alias. However, it is not the right way for the performance of the query. Here, dot notation is utilized to relate the query logic to the column name for the specific node. This method takes the XQuery statement within the normal Query and returns a single value casting with data type like as mentioned in the XQuery statement. It will fetch each node or attribute that matches the predefined node location, which may revert multiple elements, too, if multiple node locations exist with the same XPATH.
The exist XML function returns a BIT value 0 or 1 and it demonstrates that the value exists or not with the referenced arrangement. In this way, we ought to have the condition equals to 1 or 0. When a user wants to match the condition, then exist equals 1 and for unequaled, it ought to be 0.
This exist approach in the where provision consistently improves execution when we have a bigger XML with a lot of data to process. As simple as user can use multiple combination of exist , nodes , value and query in a single SQL query.
Everything depends on the query about the nature of the data to achieve better performance and business logic. A developer can implement any of the above approaches with the XML node to separate the information from the XML column or variable and by using the WHERE provision to put conditions on the same for filter out such certain values of the XML node or element. For example:. With the same path, there can be a multiple-element in the XML.
To perform the update or delete action on the specific target XML element, XQuery should be defined with the element id with [1], [2]… or apply a condition on an attribute if it exists. Within the modify function, the Replace parameter allows us to modify the value of a specific XML-tag in the XML data type column or variable. Here, the XML path can be conditional because it is possible to have the same tags multiple times on the derived path in the XML.
If multiple tags exist and the user does not validate the condition to update them, the tags can be updated by the query. See the example below:. In an XML document, different tags can exist with a similar name on the target XML path mentioned in the modify function.
So, the modify function will carry out the activity on an inappropriate XML tag which is situated in the same position in the target XML path:. When we execute the above statement without a condition, then the first fname will be updated with a new value on the targeted XML path.
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