Considering the following JSON object:
{
"users": [
{"id": "user1"},
{"id": "user2"}
],
"selected": "user1"
}
Is there a way with JSON schema to ensure that the value of the selected property is the id of one of the array items?
Sorry. You cannot do this using JSON Schema.
Related
I have a table on AWS RDS PostgreSQL that stores JSON objects. For instance I have this registry:
{
"id": "87b05c62-4153-4341-9b58-e86bade25ffd",
"title": "Just Ok",
"rating": 2,
"gallery": [
{
"id": "1cb158af-0983-4bac-9e4f-0274b3836cdd",
"typeCode": "PHOTO"
},
{
"id": "aae64f19-22a8-4da7-b40a-fbbd8b2ef30b",
"typeCode": "PHOTO"
}
],
"reviewer": {
"memberId": "2acf2ea7-7a37-42d8-a019-3d9467cbdcd1",
},
"timestamp": {
"createdAt": "2011-03-30T09:52:36.000Z",
"updatedAt": "2011-03-30T09:52:36.000Z"
},
"isUserVerified": true,
}
And I would like to create a query for obtaining one of the gallery objects.
I have tried this but get both objects in the array:
SELECT jsonb_path_query(data->'gallery', '$[*]') AS content
FROM public.reviews
WHERE jsonb_path_query_first(data->'gallery', '$.id') ? '1cb158af-0983-4bac-9e4f-0274b3836cdd'
With this other query I get the first object:
SELECT jsonb_path_query_first(data->'gallery', '$[*]') AS content
FROM public.reviews
WHERE jsonb_path_query_first(data->'gallery', '$.id') ? '1cb158af-0983-4bac-9e4f-0274b3836cdd'
But filtering by the second array object id, I get no result:
SELECT jsonb_path_query_first(data->'gallery', '$[*]') AS content
FROM public.reviews
WHERE jsonb_path_query_first(data->'gallery', '$.id') ? 'aae64f19-22a8-4da7-b40a-fbbd8b2ef30b'
I have read the official documentation and tried other functions like jsonb_path_exists or jsonb_path_match on the where condition but was not able to make the query work.
Any help would be greatly appreciated. Thanks in advance.
I managed to get the query working as needed. Here is my proposal:
SELECT gallery
FROM public.reviews, jsonb_path_query(data->'gallery', '$[*]') as gallery
WHERE data->>'id' = '87b05c62-4153-4341-9b58-e86bade25ffd' and gallery->>'id' = 'aae64f19-22a8-4da7-b40a-fbbd8b2ef30b'
Hope it helps others.
Suppose I have a json like this:
{"1": {"first_name": "a", "last_name": "b"},
"2": {"first_name": "c", "last_name": "d"}}
As you can see, values have such schema:
{"type": "object",
"properties": {
"first_name": {"type": "string"},
"last_name": {"type": "string"}
},
"additionalProperties": false,
"required": ["first_name", "last_name"]}
I want to know how can I define a schema which can validate the above json?
The additionalProperties takes a JSON Schema as it's value. (Yes, a boolean is a valid JSON Schema!)
Let's recap what the additionalProperties keyword does...
The behavior of this keyword depends on the presence and annotation
results of "properties" and "patternProperties" within the same schema
object. Validation with "additionalProperties" applies only to the
child values of instance names that do not appear in the annotation
results of either "properties" or "patternProperties".
For all such properties, validation succeeds if the child instance
validates against the "additionalProperties" schema.
https://json-schema.org/draft/2020-12/json-schema-core.html#additionalProperties
In simplest terms, if you don't use properties or patternProperties within the same schema object, the value schema of additionalProperties applies to ALL values of the applicable object in your instance.
As such, you only need to nest your existing schema as follows.
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": YOUR SCHEMA
}
I'm querying some data (SQL, presto), the source data has an array struct that includes a name and ID. I need to have an array of the IDs.
The data looks like:
[ { "id": 123456789,
"name": "name 1" },
{ "id": 234567891,
"name": "name 2" }
]
and I need it to look like:
[123456789, 234567891]
Do you know how I can achieve this?
It's: MAP_KEYS(MAP_FROM_ENTRIES(column))
I have been struggling with this problem for a long time. I need to create a new JSON flowfile using QueryRecord by taking an array (field ref) from input JSON field refs and skip the object field as shown in example below:
Input JSON flowfile
{
"name": "name1",
"desc": "full1",
"refs": {
"ref": [
{
"source": "source1",
"url": "url1"
},
{
"source": "source2",
"url": "url2"
}
]
}
}
QueryRecord configuration
JSONTreeReader setup as Infer Schema and JSONRecordSetWriter
select name, description, (array[rpath(refs, '//ref[*]')]) as sources from flowfile
Output JSON (need)
{
"name": "name1",
"desc": "full1",
"references": [
{
"source": "source1",
"url": "url1"
},
{
"source": "source2",
"url": "url2"
}
]
}
But got error:
QueryRecord Failed to write MapRecord[{references=[Ljava.lang.Object;#27fd935f, description=full1, name=name1}] with schema ["name" : "STRING", "description" : "STRING", "references" : "ARRAY[STRING]"] as a JSON Object due to java.lang.ClassCastException: null
Try the following approach, in your case it shoud work:
1) Read your JSON field fully (I imitated it with GenerateFlowFile processor with your example)
2) Add EvaluateJsonPath processor which will put 2 header fileds (name, desc) into the attributes:
3) Add SplitJson processor which will split your JSON byt refs/ref/ groups (split by "$.refs.ref"):
4) Add ReplaceText processor which will add you header fields (name, desc) to the split lines (replace "[{]" value with "{"name":"${json.name}","desc":"${json.desc}","):
5) It`s done:
Full process in my demo case:
Hope this helps.
Solution!: use JoltTransformJSON to transform JSON by Jolt specification. About this specification.
Let's say we have this json in our database table. I want to select value from tags. I already know how to get an array from this data but I don't know how to access array members. The question would be how do I get the first value from the array? Is there a function for this task?
{
"info": {
"type": 1,
"address": {
"town": "Bristol",
"county": "Avon",
"country": "England"
},
"tags": ["Sport", "Water polo"]
},
"type": "Basic"
}
Query I already have:
SELECT JSON_QUERY(MyTable.Data, '$.info.tags')
FROM MyTable
This returns me:
["Sport", "Water polo"]
How do I get
Sport
JSON_QUERY returns an object or array. You need JSON_VALUE to return a scalar value, eg :
SELECT JSON_VALUE(Data, '$.info.tags[0]')
from MyTable
Check the section Compare JSON_VALUE and JSON_QUERY in the docs for more examples