JSONB

Synopsis

Use the JSONB data type to efficiently model JSON data. This data type makes it easy to model JSON data which does not have a set schema and might change often. This data type is similar to the JSONB data type in PostgreSQL. The JSON document is serialized into a format which is easy for search and retrieval. This is achieved by storing all the JSON keys in sorted order, which allows for efficient binary search of keys. Similarly, arrays are stored such that random access for a particular array index into the serialized json document is possible.

Currently, updates to some attributes of a JSONB column require a full read-modify-write operation. Note that there are plans to enhance the JSONB data type to support efficient incremental updates in a future version.

Syntax

type_specification ::= { JSONB }

Semantics

  • Columns of type JSONB cannot be part of the PRIMARY KEY.
  • Implicitly, values of type JSONB are not convertible to other data types. JSONB types can be compared to TEXT/VARCHAR data type as long it represents valid json.
  • Values of text data types with correct format are convertible to JSONB.
  • JSONB value format supports text literals which are valid json.

Note

Internally, numbers that appear in a JSONB string (used without quotes. e.g {'a': 3.14} ) are stored as floating point values. Due to the inherent imprecision in storing floating-point numbers, one should avoid comparing them for equality. Users can either use error bounds while querying for these values in order to perform the correct floating-point comparison, or store them as strings (e.g: {'a': "3.14"}). #996 issue

Operators and functions

We currently support two operators which can be applied to the JSONB data type. The -> operator returns a result of type JSONB and further json operations can be applied to the result. The ->> operator converts JSONB to its string representation and returns the same. As a result, you can't apply further JSONB operators to the result of the ->> operator. These operators can either have a string (for keys in a json object) or integer (for array indices in a json array) as a parameter.

In some cases, you would like to process JSON attributes as numerics. For this purpose, you can use the CAST function to convert text retrieved from the ->> operator to the appropriate numeric type.

Examples

  • Create table with a JSONB column
ycqlsh> CREATE KEYSPACE store;

ycqlsh> CREATE TABLE store.books ( id int PRIMARY KEY, details jsonb );
  • Insert JSONB documents
INSERT INTO store.books (id, details) VALUES
  (1, '{ "name": "Macbeth", "author": { "first_name": "William", "last_name": "Shakespeare" }, "year": 1623, "editors": ["John", "Elizabeth", "Jeff"] }');
INSERT INTO store.books (id, details) VALUES
  (2, '{ "name": "Hamlet", "author": { "first_name": "William", "last_name": "Shakespeare" }, "year": 1603, "editors": ["Lysa", "Mark", "Robert"] }');
INSERT INTO store.books (id, details) VALUES
  (3, '{ "name": "Oliver Twist", "author": { "first_name": "Charles", "last_name": "Dickens" }, "year": 1838, "genre": "novel", "editors": ["Mark", "Tony", "Britney"] }');
INSERT INTO store.books (id, details) VALUES
  (4, '{ "name": "Great Expectations", "author": { "first_name": "Charles", "last_name": "Dickens" }, "year": 1950, "genre": "novel", "editors": ["Robert", "John", "Melisa"] }');
INSERT INTO store.books (id, details) VALUES
  (5, '{ "name": "A Brief History of Time", "author": { "first_name": "Stephen", "last_name": "Hawking" }, "year": 1988, "genre": "science", "editors": ["Melisa", "Mark", "John"] }');
  • Select from JSONB column
ycqlsh> SELECT * FROM store.books;

 id | details
----+-------------------------------------------------------------------------------------------------------------------------------------------------------------
  5 | {"author":{"first_name":"Stephen","last_name":"Hawking"},"editors":["Melisa","Mark","John"],"genre":"science","name":"A Brief History of Time","year":1988}
  1 |                            {"author":{"first_name":"William","last_name":"Shakespeare"},"editors":["John","Elizabeth","Jeff"],"name":"Macbeth","year":1623}
  4 |      {"author":{"first_name":"Charles","last_name":"Dickens"},"editors":["Robert","John","Melisa"],"genre":"novel","name":"Great Expectations","year":1950}
  2 |                                {"author":{"first_name":"William","last_name":"Shakespeare"},"editors":["Lysa","Mark","Robert"],"name":"Hamlet","year":1603}
  3 |             {"author":{"first_name":"Charles","last_name":"Dickens"},"editors":["Mark","Tony","Britney"],"genre":"novel","name":"Oliver Twist","year":1838}
  • Select with condition on JSONB object value
ycqlsh> SELECT * FROM store.books WHERE details->'author'->>'first_name' = 'William' AND details->'author'->>'last_name' = 'Shakespeare';

 id | details
----+----------------------------------------------------------------------------------------------------------------------------------
  1 | {"author":{"first_name":"William","last_name":"Shakespeare"},"editors":["John","Elizabeth","Jeff"],"name":"Macbeth","year":1623}
  2 |     {"author":{"first_name":"William","last_name":"Shakespeare"},"editors":["Lysa","Mark","Robert"],"name":"Hamlet","year":1603}
  • Select with condition on JSONB array element
ycqlsh> SELECT * FROM store.books WHERE details->'editors'->>0 = 'Mark';

 id | details
----+-------------------------------------------------------------------------------------------------------------------------------------------------
  3 | {"author":{"first_name":"Charles","last_name":"Dickens"},"editors":["Mark","Tony","Britney"],"genre":"novel","name":"Oliver Twist","year":1838}
  • Select with condition using on JSONB element
ycqlsh> SELECT * FROM store.books WHERE CAST(details->>'year' AS integer) = 1950;

 id | details
----+--------------------------------------------------------------------------------------------------------------------------------------------------------
  4 | {"author":{"first_name":"Charles","last_name":"Dickens"},"editors":["Robert","John","Melisa"],"genre":"novel","name":"Great Expectations","year":1950}
  • Update entire JSONB document

You can do this as shown below.

ycqlsh> UPDATE store.books SET details = '{"author":{"first_name":"Carl","last_name":"Sagan"},"editors":["Ann","Rob","Neil"],"genre":"science","name":"Cosmos","year":1980}' WHERE id = 1;

ycqlsh> SELECT * FROM store.books WHERE id = 1;

 id | details
----+-----------------------------------------------------------------------------------------------------------------------------------
  1 | {"author":{"first_name":"Carl","last_name":"Sagan"},"editors":["Ann","Rob","Neil"],"genre":"science","name":"Cosmos","year":1980}
  • Update a JSONB object value.
ycqlsh> UPDATE store.books SET details->'author'->>'first_name' = '"Steve"' WHERE id = 4;

ycqlsh> SELECT * FROM store.books WHERE id = 4;

 id | details
----+------------------------------------------------------------------------------------------------------------------------------------------------------
  4 | {"author":{"first_name":"Steve","last_name":"Dickens"},"editors":["Robert","John","Melisa"],"genre":"novel","name":"Great Expectations","year":1950}
  • Update a JSONB array element.
ycqlsh> UPDATE store.books SET details->'editors'->>1 = '"Jack"' WHERE id = 4;

ycqlsh> SELECT * FROM store.books WHERE id = 4;

 id | details
----+------------------------------------------------------------------------------------------------------------------------------------------------------
  4 | {"author":{"first_name":"Steve","last_name":"Dickens"},"editors":["Robert","Jack","Melisa"],"genre":"novel","name":"Great Expectations","year":1950}
  • Update a JSONB subdocument.
ycqlsh> UPDATE store.books SET details->'author' = '{"first_name":"John", "last_name":"Doe"}' WHERE id = 4;

ycqlsh> SELECT * FROM store.books WHERE id = 4;

 id | details
----+-------------------------------------------------------------------------------------------------------------------------------------------------
  4 | {"author":{"first_name":"John","last_name":"Doe"},"editors":["Robert","Jack","Melisa"],"genre":"novel","name":"Great Expectations","year":1950}
  • Upsert: Update a missing JSONB document resulting in an insert.
INSERT INTO store.books (id, details) VALUES
  (6, '{}');
ycqlsh> UPDATE store.books SET details->'editors' = '["Adam", "Bryan", "Charles"]' WHERE id = 6;

ycqlsh> SELECT * FROM store.books WHERE id = 6;

 id | details
----+-------------------------------------------------------------------------------------------------------------------------------------------------
  6 | {"editors":["Adam","Bryan","Charles"]}
  • Upsert: Update a missing JSONB document resulting in an insert of a subdocument.
ycqlsh> UPDATE store.books SET details->'author' = '{"first_name":"Jack", "last_name":"Kerouac"}' WHERE id = 6;

ycqlsh> SELECT * FROM store.books WHERE id = 6;

 id | details
----+-------------------------------------------------------------------------------------------------------------------------------------------------
  6 | {"author":{"first_name":"Jack","last_name":"Kerouac"},"editors":["Adam","Bryan","Charles"]}

Note that JSONB upsert only works for JSON objects and not for other data types like arrays, integers, strings, etc. Additionally, only the leaf property of an object will be inserted if it is missing. We do not support upsert on non-leaf properties.

See also