Dialect Specific Data Type

Write new Dialect

GORM provides supports for sqlite, mysql, postgres, mssql officially.

You could add other database support by creating a new dialect, need to implement the dialect interface.

Some databases might compatible with mysql or postgres dialect, then you could just use the dialect for those databases.

Dialect Specific Data Type

Certain dialects of SQL ship with their own custom, non-standard column types, such as the jsonb column in PostgreSQL. GORM supports loading several of such types, as listed in the following sections.

PostgreSQL

GORM supports loading the following PostgreSQL exclusive column types:

  • jsonb
  • hstore

Given the following Model definition:

import (
"encoding/json"
"github.com/jinzhu/gorm/dialects/postgres"
)

type Document struct {
Metadata postgres.Jsonb
Secrets postgres.Hstore
Body string
ID int
}

You may use the model like so:

password := "0654857340"
metadata := json.RawMessage(`{"is_archived": 0}`)
sampleDoc := Document{
Body: "This is a test document",
Metadata: postgres.Jsonb{ metadata },
Secrets: postgres.Hstore{"password": &password},
}

//insert sampleDoc into the database
db.Create(&sampleDoc)

//retrieve the fields again to confirm if they were inserted correctly
resultDoc := Document{}
db.Where("id = ?", sampleDoc.ID).First(&resultDoc)

metadataIsEqual := reflect.DeepEqual(resultDoc.Metadata, sampleDoc.Metadata)
secretsIsEqual := reflect.DeepEqual(resultDoc.Secrets, resultDoc.Secrets)

// this should print "true"
fmt.Println("Inserted fields are as expected:", metadataIsEqual && secretsIsEqual)