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Version: 5.9

Using JSON properties

Defining JSON properties

Each database driver behaves a bit differently when it comes to JSON properties. MikroORM tries to unify the experience via JsonType. This type will be also used if we specify type: 'json'.

export class Book {

@Property({ type: 'json', nullable: true })
meta?: { foo: string; bar: number };


Querying by JSON object properties

Support for querying by JSON object properties was added in v4.4.2

We can query by JSON object properties easily:

const b = await em.findOne(Book, {
meta: {
valid: true,
nested: {
foo: '123',
bar: 321,
deep: {
baz: 59,
qux: false,

Will produce following query (in postgres):

select "e0".*
from "book" as "e0"
where ("meta"->>'valid')::bool = true
and "meta"->'nested'->>'foo' = '123'
and ("meta"->'nested'->>'bar')::float8 = 321
and ("meta"->'nested'->'deep'->>'baz')::float8 = 59
and ("meta"->'nested'->'deep'->>'qux')::bool = false
limit 1

All drivers are currently supported (including sqlite and mongo). In postgres we also try to cast the value if we detect number or boolean on the right-hand side.