XML data, however, has its own, fine-grained structure, which is not necessarily reflected in the structure of the database tables used to store it.For this reason, effectively indexing XML data can be a bit different from indexing most database data.instance, which means that you can directly access its members.Because the structured storage model directly reflects the fine-grained structure of the XML data, you can create indexes that target individual collection members. The special feature of automatically creating B-tree indexes when you ostensibly create a function-based index for (deprecated) Oracle SQL function must target a singleton).
applications, which often contain a mix of XML elements and text-node content.It is also possible to specify an absolute location, but beware that you must use URL syntax, not Path syntax.You can create indexes on your XML data, to focus on particular parts of it that you query often and thus improve performance. It describes various ways that you can index Database indexes improve performance by providing faster access to table data.However, just because an index is defined and it might appear applicable in a given situation does not mean that it will be used — it will not be used if the cost-based optimizer deems that its use is not cost-effective. Doing so obviates the overhead associated with maintenance operations on function-based indexes, and it increases the number of situations in which the optimizer can correctly select the index.No changes to existing DML statements are required as a result of this.