Dialect Specific Data Type

新しい方言を書く

GORM provides official support for sqlite, mysql, postgres, mssql.

You can add support for additional databases by creating a new dialect. When creating a new dialect, you must implement the dialect interface.

Some databases may be compatible with the mysql or postgres dialect, in which case you could just use the dialect for those databases.

方言に特化したデータ型

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 these 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, sampleDoc.Secrets)

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