Section 8.14.4 describes how these operators can be used to effectively index jsonb data. For a full description of jsonb containment and existence semantics, see Section 8.14.3. Many of these operators can be indexed by jsonb operator classes. Some further operators also exist only for jsonb, as shown in Table 9-41. Adds jsonb (b for "binary", values are stored as native Postgres types) and yet more functionality for both types. Query combinations with nested array of records in JSON datatype For bigger tables you may want to add an expression index to increase performance: Index for finding an element in a JSON array Postgres 9.4. Because the -> operator returns an object, you can chain it to inspect deep into a JSON document. These operators work on both JSON as well as JSONB columns. The first operator -> returns a JSON object, while the operator -> returns text. PostgreSQL has two native operators -> and -> to query JSON documents. Here's how you can query your JSON column in PostgreSQL: - Give me params.name (text) from the events table One of PostgreSQL's benefits is that it's a relational database, but you can also get the advantages of unstructured data by storing things in a JSON column. Otherwise, if there is a cast from the SQL data type to json, the cast function will be used to perform the conversion otherwise, a scalar JSON value is produced. Arrays and composites are converted recursively to arrays and objects (multidimensional arrays become arrays of arrays in JSON). A PostgreSQL multidimensional array becomes a JSON array of arrays.Ĭonverts any SQL value to json or jsonb. PostgreSQL supports native JSON data type since version 9.2.įunction Return Type Description Example Example Result array_to_json(anyarray ) json: Returns the array as JSON. Unlike other formats, JSON is human-readable text. The main usage of JSON is to transport data between a server and a web application. JSON is an open standard format that consists of key-value pairs.
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