Techniques for changing XML content in a relational database

A method for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving an SQL statement that includes an insert operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct,
• data that indicates a name an element for the first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the insert operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that is a child XML element of the first XML construct and has an XML element name based on the data that indicates the name.

A method for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving an SQL statement that includes an insert-before operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the insert-before operator by generating, based on the expression for the particular value, a second component representing a second XML construct inserted before the first XML construct in the instance of XML type in XML document order.

A method for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving an SQL statement that includes an append-child operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the append-child operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that is a child of the first XML construct in the instance of XML type.

A method for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving a SQL statement that includes an update operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the update operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that replaces the first XML construct in the instance of XML type.

A method for executing database update commands on extensible markup language (XML constructs in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving a database modification statement to modify a first component in an instance of XML type, wherein the first component represents a first XML construct;
• and
• during execution of the database modification statement, evaluating the database modification statement, including
• determining, of the instance of XML type, a first portion that is affected by executing the database modification statement, wherein the first portion is less than all of the instance of XML type;
• and
• mapping the first portion to a first set of at least one SQL construct;
• and
• updating the first set of at least one SQL construct without updating a second set of at least one SQL construct that represents a second portion of the instance of XML type, wherein the second portion is not affected by executing the database modification statement.

A method for executing database update commands on extensible markup language (XML) constructs in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, comprising the steps of:

• receiving a database modification statement to modify a first component in an instance of XML type, wherein the first component represents a first XML construct;
• compiling the database modification statement, including:
• determining a particular set of one or more SQL constructs that are affected by the database modification statement;
• and
• rewriting the database modification statement as a set of one or more SQL operations on the particular set of one or more SQL constructs;
• and
• evaluating the database modification statement by evaluating the set of one or more SQL operations on the particular set of one or more SQL constructs.

A computer-readable medium carrying one or more sequences of instructions for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving an SQL statement that includes an insert operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct,
• data that indicates a name of an element for the first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the insert operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that is a child XML element of the first XML construct and has an XML element name based on the data that indicates the name.

A computer-readable medium carrying one or more sequences of instructions for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving an SQL statement that includes an insert-before operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the insert-before operator by generating, based on the expression for the particular value, a second component that represents a second XML construct inserted before the first XML construct in thee instance of XML type in XML document order.

A computer-readable medium carrying one or more sequences of instructions for changing data for an eXtensible Markup Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving an SQL statement that includes an append-child operator that operates on a first components in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular vale for XML content;
• and
• during execution of the SQL statement, evaluating the append-child operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that is a child of the first XML construct in the instance of XML type.

A computer-readable medium carrying one or more sequences of instructions for changing data for an eXtensible Markup-Language (XML) construct in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving a SQL statement that includes an update operator that operates on a first component in an instance of XML type, wherein the first component represents a first XML construct, and
• an expression for a particular value for XML content;
• and
• during execution of the SQL statement, evaluating the update operator by generating, based on the expression for the particular value, a second component that represents a second XML construct that replaces the first XML construct in the instance of XML type.

A computer-readable medium carrying one or more sequences of instructions for executing database update commands on extensible markup language (XML) constructs in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving a database modification statement to modify a first component in an instance of XML type, wherein the first component represents a first XML construct;
• and
• during execution of the database modification statement, evaluating the database modification statement, including
• determining, of the instance of XML type, a first portion that is affected by executing the database modification statement, wherein the first portion is less than all of the instance of XML type;
• and
• mapping the first portion to a first set of at least one SQL construct;
• and
• updating the first set of at least one SQL construct without updating a second set of at least one SQL construct that represents a second portion of the instance of XML type, wherein the second portion is not affected by executing the database modification statement.

A computer-readable medium carrying one or more sequences of instructions for executing database update commands on extensible markup language (XML) constructs in a Structured Query Language (SQL) compliant database management system (DBMS) that allows instances of XML type to represent XML constructs, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

• receiving a database modification statement to modify a first component in an instance of XML type, wherein the first component represents a first XML construct;
• compiling the database modification statement, including:
• determining a particular set of one or more SQL constructs that are affected by the database modification statement;
• and
• rewriting the database modification statement as a set of one or more SQL operations on the particular set of one or more SQL constructs;
• and
• evaluating the database modification statement by evaluating the set of one or more SQL operations on the particular set of one or more SQL constructs.