This tutorial shows you how build a simple Go application with CockroachDB using a PostgreSQL-compatible driver or ORM.

We have tested the Go pq driver and the GORM ORM enough to claim beta-level support, so those are featured here. If you encounter problems, please open an issue with details to help us make progress toward full support.

Tip:

For a more realistic use of GORM with CockroachDB, see our examples-orms repository.

Before you begin

  1. Install CockroachDB.
  2. Start up a secure or insecure local cluster.
  3. Choose the instructions that correspond to whether your cluster is secure or insecure:

Step 1. Install the GORM ORM

To install GORM, run the following commands:

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$ go get -u github.com/lib/pq # dependency
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$ go get -u github.com/jinzhu/gorm

Step 2. Create the maxroach user and bank database

Start the built-in SQL client:

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$ cockroach sql --certs-dir=certs

In the SQL shell, issue the following statements to create the maxroach user and bank database:

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> CREATE USER IF NOT EXISTS maxroach;
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> CREATE DATABASE bank;

Give the maxroach user the necessary permissions:

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> GRANT ALL ON DATABASE bank TO maxroach;

Exit the SQL shell:

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> \q

Step 3. Generate a certificate for the maxroach user

Create a certificate and key for the maxroach user by running the following command. The code samples will run as this user.

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$ cockroach cert create-client maxroach --certs-dir=certs --ca-key=my-safe-directory/ca.key

Step 4. Run the Go code

The following code uses the GORM ORM to map Go-specific objects to SQL operations. Specifically, db.AutoMigrate(&Account{}) creates an accounts table based on the Account model, db.Create(&Account{}) inserts rows into the table, and db.Find(&accounts) selects from the table so that balances can be printed.

Copy the code or download it directly.

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package main

import (
    "fmt"
    "log"

    // Import GORM-related packages.
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/postgres"
)

// Account is our model, which corresponds to the "accounts" database table.
type Account struct {
    ID      int `gorm:"primary_key"`
    Balance int
}

func main() {
    // Connect to the "bank" database as the "maxroach" user.
    const addr = "postgresql://maxroach@localhost:26257/bank?ssl=true&sslmode=require&sslrootcert=certs/ca.crt&sslkey=certs/client.maxroach.key&sslcert=certs/client.maxroach.crt"
    db, err := gorm.Open("postgres", addr)
    if err != nil {
        log.Fatal(err)
    }
    defer db.Close()

    // Automatically create the "accounts" table based on the Account model.
    db.AutoMigrate(&Account{})

    // Insert two rows into the "accounts" table.
    db.Create(&Account{ID: 1, Balance: 1000})
    db.Create(&Account{ID: 2, Balance: 250})

    // Print out the balances.
    var accounts []Account
    db.Find(&accounts)
    fmt.Println("Initial balances:")
    for _, account := range accounts {
        fmt.Printf("%d %d\n", account.ID, account.Balance)
    }
}

Then run the code:

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$ go run gorm-basic-sample.go

The output should be:

Initial balances:
1 1000
2 250

To verify that funds were transferred from one account to another, start the built-in SQL client:

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$ cockroach sql --certs-dir=certs -e 'SELECT id, balance FROM accounts' --database=bank
+----+---------+
| id | balance |
+----+---------+
|  1 |    1000 |
|  2 |     250 |
+----+---------+
(2 rows)

Step 2. Create the maxroach user and bank database

Start the built-in SQL client:

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$ cockroach sql --insecure

In the SQL shell, issue the following statements to create the maxroach user and bank database:

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> CREATE USER IF NOT EXISTS maxroach;
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> CREATE DATABASE bank;

Give the maxroach user the necessary permissions:

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> GRANT ALL ON DATABASE bank TO maxroach;

Exit the SQL shell:

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> \q

Step 3. Run the Go code

The following code uses the GORM ORM to map Go-specific objects to SQL operations. Specifically, db.AutoMigrate(&Account{}) creates an accounts table based on the Account model, db.Create(&Account{}) inserts rows into the table, and db.Find(&accounts) selects from the table so that balances can be printed.

Copy the code or download it directly.

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package main

import (
    "fmt"
    "log"

    // Import GORM-related packages.
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/postgres"
)

// Account is our model, which corresponds to the "accounts" database table.
type Account struct {
    ID      int `gorm:"primary_key"`
    Balance int
}

func main() {
    // Connect to the "bank" database as the "maxroach" user.
    const addr = "postgresql://maxroach@localhost:26257/bank?sslmode=disable"
    db, err := gorm.Open("postgres", addr)
    if err != nil {
        log.Fatal(err)
    }
    defer db.Close()

    // Automatically create the "accounts" table based on the Account model.
    db.AutoMigrate(&Account{})

    // Insert two rows into the "accounts" table.
    db.Create(&Account{ID: 1, Balance: 1000})
    db.Create(&Account{ID: 2, Balance: 250})

    // Print out the balances.
    var accounts []Account
    db.Find(&accounts)
    fmt.Println("Initial balances:")
    for _, account := range accounts {
        fmt.Printf("%d %d\n", account.ID, account.Balance)
    }
}

Then run the code:

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$ go run gorm-basic-sample.go

The output should be:

Initial balances:
1 1000
2 250

To verify that funds were transferred from one account to another, start the built-in SQL client:

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$ cockroach sql --insecure -e 'SELECT id, balance FROM accounts' --database=bank
+----+---------+
| id | balance |
+----+---------+
|  1 |    1000 |
|  2 |     250 |
+----+---------+
(2 rows)

What's next?

Read more about using the GORM ORM, or check out a more realistic implementation of GORM with CockroachDB in our examples-orms repository.

You might also be interested in using a local cluster to explore the following CockroachDB benefits:



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