.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
-.. Copyright (C) 2021-2022 Nordix Foundation
+.. Copyright (C) 2021-2023 Nordix Foundation
+.. Modifications Copyright (C) 2023 TechMahindra Ltd
.. DO NOT CHANGE THIS LABEL FOR RELEASE NOTES - EVEN THOUGH IT GIVES A WARNING
-.. _design:
+.. _path:
CPS Path
=============
- String values must be wrapped in quotation marks ``"`` (U+0022) or apostrophes ``'`` (U+0027).
+- Quotations marks and apostrophes can be escaped by doubling them in their respective quotes, for example ``'CPS ''Path'' Query' -> CPS 'Path' Query``
- String comparisons are case sensitive.
-- List key-fields containing ``\`` or ``@[`` will not be processed correctly when being referenced with such key values in absolute or descendant paths. This means such entries will be omitted from any query result. See `CPS-500 <https://jira.onap.org/browse/CPS-500>`_ Special Character Limitations of cpsPath Queries
Query Syntax
============
-``( <absolute-path> | <descendant-path> ) [ <leaf-conditions> ] [ <text()-condition> ] [ <ancestor-axis> ]``
+``( <absolute-path> | <descendant-path> ) [ <leaf-conditions> ] [ <text()-condition> ] [ <contains()-condition> ] [ <ancestor-axis> ]``
Each CPS path expression need to start with an 'absolute' or 'descendant' xpath.
**Limitations**
- Absolute paths must start with the top element (data node) as per the model tree.
- Each list reference must include a valid instance reference to the key for that list. Except when it is the last element.
- - The Absolute path to list with integer key will not work. It needs to be surrounded with a single quote ([@code='1'])
- as if it is a string. This will be fixed in `CPS-961 <https://jira.onap.org/browse/CPS-961>`_
descendant-path
---------------
leaf-conditions
---------------
-**Syntax**: ``<xpath> '[' @<leaf-name1> '=' <leaf-value1> ( ' and ' @<leaf-name> '=' <leaf-value> )* ']'``
+**Syntax**: ``<xpath> '[' @<leaf-name1> '(=|>|<|>=|<=)' <leaf-value1> ( ' <and|or> ' @<leaf-name> '(=|>|<|>=|<=)' <leaf-value> )* ']'``
- ``xpath``: Absolute or descendant or xpath to the (list) node which elements will be queried.
- ``leaf-name``: The name of the leaf which value needs to be compared.
- ``leaf-value``: The required value of the leaf.
- ``//categories[@name="Kids"]``
- ``//categories[@name='Kids']``
- ``//categories[@code='1']/books/book[@title='Dune' and @price=5]``
-
+ - ``//categories[@code='1']/books/book[@title='xyz' or @price=15]``
+ - ``//categories[@code='1']/books/book[@title='xyz' or @price>20]``
+ - ``//categories[@code='1']/books/book[@title='Dune' and @price<=5]``
+ - ``//categories[@code=1]``
**Limitations**
- Only the last list or container can be queried leaf values. Any ancestor list will have to be referenced by its key name-value pair(s).
- - Multiple attributes can only be combined using ``and``. ``or`` and bracketing is not supported.
+ - When mixing ``and/or`` operators, ``and`` has precedence over ``or`` . So ``and`` operators get evaluated first.
+ - Bracketing is not supported.
+ - Leaf names are not validated so ``or`` operations with invalid leaf names will silently be ignored.
- Only leaves can be used, leaf-list are not supported.
- Only string and integer values are supported, boolean and float values are not supported.
+ - Using comparative operators with string values will lead to an error at runtime. This error can't be validated earlier as the datatype is unknown until the execution phase.
+ - The key should be supplied with correct data type for it to be queried from DB. In the last example above the attribute code is of type
+ Integer so the cps query will not work if the value is passed as string.
+ e.g.: ``//categories[@code="1"]`` or ``//categories[@code='1']`` will not work because the key attribute code is treated a string.
**Notes**
- For performance reasons it does not make sense to query using key leaf as attribute. If the key value is known it is better to execute a get request with the complete xpath.
**Syntax**: ``<cps-path> ( '/' <leaf-name> '[text()=' <string-value> ']' )?``
- ``cps-path``: Any CPS path query.
- ``leaf-name``: The name of the leaf or leaf-list which value needs to be compared.
- - ``string-value``: The required value of the leaf or leaf-list element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This wil still match integer values.
+ - ``string-value``: The required value of the leaf or leaf-list element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This will still match integer values.
**Examples**
- ``//book/label[text()="classic"]``
- Since CPS cannot return individual leaves it will always return the container with all its leaves. Ancestor-axis can be used to specify a parent higher up the tree.
- When querying a leaf value (instead of leaf-list) it is better, more performant to use a text value condition use @<leaf-name> as described above.
+contains()-condition
+--------------------
+
+**Syntax**: ``<cps-path> '[' 'contains' '(' '<leaf-name>','<string-value>' ')' ']'?``
+ - ``cps-path``: Any CPS path query.
+ - ``leaf-name``: The name of the leaf which value needs to be compared.
+ - ``string-value``: The required value of the leaf element as a string wrapped in quotation marks (U+0022) or apostrophes (U+0027). This will still match integer values.
+
+**Examples**
+ - ``//categories[contains(@name,'Sci')]``
+ - ``//books[contains(@title,'Space')]``
+
+**Limitations**
+ - Only leaves can be used, leaf-list are not supported.
+ - Leaf names are not validated so ``contains() condition`` with invalid leaf names will silently be ignored.
+
+**Notes**
+ - contains condition is case sensitive.
+
ancestor-axis
-------------
Code Review / cps.git / blobdiff