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we would like to bring support for contains operator in cps-path.

...

Issues & decisions

Native query for Contains Operator using Like Keyword :

#	Issue	Notes	Decisions
1	Which keyword to use ? Do we want case sensitivity or not? Do we follow the Xpath contains or do we become specific?	like %en% ilike %En% like 'en'	27 Mar 2023 As per discussion , with Toine Siebelink , community call like keyword would has consistency which support case sensitive attribute values. Need to discuss with stakeholders. 29 Mar 2023 As per discussion in community call , decided to go with like keyword more consistent support case sensitivity.

#

Json Data

CPS-PATH Syntax

Output

1

Below is the sample data ,
Here are ways to use contains keyword :

Code Block

title	Json data
collapse	true

{
   "test:bookstore":{
      "bookstore-name": "Chapters",
      "categories": [
         {
            "code": "01",
            "name": "SciFi",
            "books": [
               {
                  "authors": [
                     "Iain M. Banks"
                  ],
                  "lang": "english",
                  "price": "895",
                  "pub_year": "1994",
                  "title": "Feersum Endjinn"
               }
            ]
         },
         {
            "name": "kids",
            "code": "02",
            "books": [
               {
                  "authors": [
                     "Philip Pullman"
                  ],
                  "lang": "Science",
                  "price": "699",
                  "pub_year": "1995",
                  "title": "The Golden Compass"
               }
            ]
         }
    ]
   }
}

<cps-path>(contains'[@leafname,'<string-value>']')

Examples

```
//books[contains(@lang,'en')
```
```
//books[contains(@pub_year,'99')
```

Code Block

title	Json Response
collapse	true

{
 "lang": "en", 
 "price": 895, 
 "title": "Feersum Endjinn", 
 "authors": [
            "Iain M. Banks"
 ], 
"pub_year":1994
}  
{
 "lang": "en", 
 "price": 699, 
 "title": "The Golden Compass", 
 "authors": [
           "Philip Pullman"
 ], 
"pub_year":1995
}

Native Query for contains keyword

...

_ : Matches any single character.

#	Query	Output

Decision

1

cpsdb=# SELECT * FROM FRAGMENT WHERE anchor_id = 4 and attributes->>'lang' like '%en%';

Code Block

title	Json Response
collapse	true

{
 "lang": "en", 
 "price": 699, 
 "title": "The Golden Compass", 
 "authors": [
           "Philip Pullman"
 ], 
"pub_year":1995
}                                                                                                
{
 "lang": "english", 
 "price": 895, 
 "title": "Feersum Endjinn", 
 "authors": [
            "Iain M. Banks"
 ], 
"pub_year":1994
}

2

cpsdb=# SELECT * FROM FRAGMENT WHERE anchor_id = 4 and attributes->>'lang' ilike '%En%';

Code Block

title	Json Response
collapse	true

{
 "lang": "en", 
 "price": 699, 
 "title": "The Golden Compass", 
 "authors": [
           "Philip Pullman"
 ], 
"pub_year":1995
}                                                                                                
{
 "lang": "English", 
 "price": 895, 
 "title": "Feersum Endjinn", 
 "authors": [
            "Iain M. Banks"
 ], 
"pub_year":1994
}

27 Mar 2023

As per discussion , with Toine Siebelink Contains Xpath is case sensitive , So ilike keyword would be suitable to implement the contains query which support case sensitive attribute values

3

cpsdb=# SELECT * FROM FRAGMENT WHERE anchor_id = 4 and attributes->>'lang' like 'en';

Code Block

title	Json Response
collapse	true

{
 "lang": "en", 
 "price": 699, 
 "title": "The Golden Compass", 
 "authors": [
           "Philip Pullman"
 ], 
"pub_year":1995
}

2.Using SIMILAR TO Regular Expression Keyword :

The only difference between like and similar to is to pattern matches the given string. It is similar to LIKE, except that it interprets the pattern using the SQL standard's definition of a regular expression

SIMILAR TO supports these pattern-matching metacharacters borrowed from POSIX regular expressions:

| denotes alternation (either of two alternatives).
* denotes repetition of the previous item zero or more times.
+ denotes repetition of the previous item one or more times.
? denotes repetition of the previous item zero or one time.
{m} denotes repetition of the previous item exactly m times.
{m,} denotes repetition of the previous item m or more times.
{m,n} denotes repetition of the previous item at least m and not more than n times.
Parentheses () can be used to group items into a single logical item.
A bracket expression [...] specifies a character class, just as in POSIX regular expressions.

Query

Output

1

cpsdb=# SELECT * FROM FRAGMENT WHERE anchor_id = 3 and attributes->>'pub_year'similar to '%(94|95)%';

Code Block

title	Json Response
collapse	true

{
 "lang": "en", 
 "price": 699, 
 "title": "The Golden Compass", 
 "authors": [
           "Philip Pullman"
 ], 
"pub_year":1995
}                                                                                               
{
 "lang": "english", 
 "price": 895, 
 "title": "Feersum Endjinn", 
 "authors": [
            "Iain M. Banks"
 ], 
"pub_year":1994
}

Performance wise : As we are not making much changes for query , the performance is similar to existing query will not effect much

Implementation of Contains Operator

1.Update antlr parser to recognize this pattern
2.Implement required (native) query
3.Add

...

Integration tests for
a.filter on string leaf-value
b.filter on Integer

...

leaf-

...

value
4.Update documentation
5.demo to team

Limitations

1. contains condition is case sensitive.
2. Only leaves can be used, leaf-list are not supported.
3. Only string and integer values are supported, boolean and float values are not supported.
4. When empty value is passed with contains it returns all the nodes that has given leaf element.

Versions Compared

Old Version 18

New Version Current

Key

Native Query for contains keyword

Implementation of Contains Operator

Limitations