Connect an application

• YugabyteDB PGX Smart Driver
• PGX Driver
• PQ Driver

The PQ driver is a popular driver for PostgreSQL. Use the driver to connect to YugabyteDB to execute DMLs and DDLs using the standard database/sql package.

CRUD operations

For Go Applications, most drivers provide database connectivity through the standard database/sql API. Learn how to establish a connection to YugabyteDB database and begin basic CRUD operations using the steps in Build an application.

The following sections break down the example to demonstrate how to perform common tasks required for Go application development using the PQ driver.

Step 1: Import the driver package

Import the PQ driver package by adding the following import statement in your Go code.

import (
  _ "github.com/lib/pq"
)

Step 2: Set up the database connection

Go applications can connect to YugabyteDB using the sql.Open() function. The sql package includes all the functions or structs required for working with YugabyteDB.

Use the sql.Open() function to create a connection object for the YugabyteDB database. This can be used for performing DDLs and DMLs against the database.

The connection details can be specified either as string parameters or via a URL in the following format:

postgresql://username:password@hostname:port/database

Code snippet for connecting to YugabyteDB:

psqlInfo := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s",
                        host, port, user, password, dbname)
// Other connection configs are read from the standard environment variables:
// PGSSLMODE, PGSSLROOTCERT, and so on.
db, err := sql.Open("postgres", psqlInfo)
defer db.Close()
if err != nil {
    log.Fatal(err)
}

Use SSL

For a YugabyteDB Managed cluster, or a YugabyteDB cluster with SSL/TLS enabled, set the SSL-related environment variables as below at the client side. SSL/TLS is enabled by default for client-side authentication. Refer to OpenSSL for the default and supported modes.

$ export PGSSLMODE=verify-ca
$ export PGSSLROOTCERT=~/root.crt  # Here, the CA certificate file is downloaded as `root.crt` under home directory. Modify your path accordingly.

Step 3: Create tables

Execute an SQL statement such as DDL CREATE TABLE ... using the Exec() function on the db instance.

The CREATE DDL statement:

CREATE TABLE employee (id int PRIMARY KEY, name varchar, age int, language varchar)

Code snippet:

var createStmt = `CREATE TABLE employee (id int PRIMARY KEY,
                                         name varchar,
                                         age int,
                                         language varchar)`;
if _, err := db.Exec(createStmt); err != nil {
    log.Fatal(err)
}

The db.Exec() function also returns an error object which, if not nil, needs to be handled in your code.

Read more on designing Database schemas and tables.

Step 4: Read and write data

Insert data

To write data into YugabyteDB, execute the INSERT statement using the same db.Exec() function.

The INSERT DML statement:

INSERT INTO employee(id, name, age, language) VALUES (1, 'John', 35, 'Go')

Code snippet:

var insertStmt string = "INSERT INTO employee(id, name, age, language)" +
    " VALUES (1, 'John', 35, 'Go')";
if _, err := db.Exec(insertStmt); err != nil {
    log.Fatal(err)
}

Query data

To query data from YugabyteDB tables, execute the SELECT statement using the function Query() on db instance.

Query results are returned as rows which can be iterated using rows.next() method. Use rows.Scan() for reading the data.

The SELECT DML statement:

SELECT * from employee;

Code snippet:

var name string
var age int
var language string
rows, err := db.Query(`SELECT name, age, language FROM employee WHERE id = 1`)
if err != nil {
    log.Fatal(err)
}
defer rows.Close()
fmt.Printf("Query for id=1 returned: ");
for rows.Next() {
    err := rows.Scan(&name, &age, &language)
    if err != nil {
       log.Fatal(err)
    }
    fmt.Printf("Row[%s, %d, %s]\n", name, age, language)
}
err = rows.Err()
if err != nil {
    log.Fatal(err)
}

Learn more

• Build Go applications using GORM
• Go driver reference