Go Drivers
The PQ driver is a popular driver for PostgreSQL that can used for connecting to YugabyteDB YSQL.
The driver allows Go programmers to connect to YugabyteDB database to execute DMLs and DDLs using the standard database/sql
package.
Fundamentals
Learn how to perform common tasks required for Go application development using the YugabyteDB PQ driver.
Import the driver package
Import the PQ driver package by adding the following import statement in your Go code.
import (
_ "github.com/lib/pq"
)
Connect to YugabyteDB database
Go Apps can connect to the YugabyteDB database using the sql.Open()
function. All the functions or structs required for working with YugabyteDB database are part of sql
package.
Use the sql.Open()
function to get the connection object for the YugabyteDB database which can be used for performing DDLs and DMLs against the database.
The connection details can be specified either as string parameters or via an 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)
}
Parameters | Description | Default |
---|---|---|
host | hostname of the YugabyteDB instance | localhost |
port | Listen port for YSQL | 5433 |
user | user for connecting to the database | yugabyte |
password | password for connecting to the database | yugabyte |
dbname | database name | yugabyte |
Create table
Execute an SQL statement like the 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 handled in your code.
Read more on designing Database schemas and tables.
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)
}
Configure SSL/TLS
To build a Go application that communicates securely over SSL with YugabyteDB database, you need the root certificate (ca.crt
) of the YugabyteDB Cluster.
To generate these certificates and install them while launching the cluster, follow the instructions in Create server certificates.
For a YugabyteDB Managed cluster, or a YugabyteDB cluster with SSL/TLS enabled, set the SSL-related environment variables at the client side.
$ 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.
Environment Variable | Description |
---|---|
PGSSLMODE | SSL mode used for the connection |
PGSSLROOTCERT | Server CA Certificate |
SSL modes
Install OpenSSL 1.1.1 or later only if you have a YugabyteDB setup with SSL/TLS enabled. YugabyteDB Managed clusters are always SSL/TLS enabled.
The following table summarizes the SSL modes and their support in the driver:
SSL Mode | Client Driver Behavior | YugabyteDB Support |
---|---|---|
disable | SSL Disabled | Supported |
allow | SSL enabled only if server requires SSL connection | Supported |
prefer (default) | SSL enabled only if server requires SSL connection | Supported |
require | SSL enabled for data encryption and Server identity is not verified | Supported |
verify-ca | SSL enabled for data encryption and Server CA is verified | Supported |
verify-full | SSL enabled for data encryption. Both CA and hostname of the certificate are verified | Supported |
YugabyteDB Managed requires SSL/TLS, and connections using SSL mode disable
will fail.
Transaction and isolation levels
YugabyteDB supports transactions for inserting and querying data from the tables. YugabyteDB supports different isolation levels for maintaining strong consistency for concurrent data access.
The PQ driver provides db.Begin()
function to start a transaction. The function conn.BeginEx()
can create a transaction with a specified isolation level.`
tx, err := db.Begin()
if err != nil {
log.Fatal(err)
}
...
_, err = stmt.Exec()
if err != nil {
log.Fatal(err)
}
err = stmt.Close()
if err != nil {
log.Fatal(err)
}
err = txn.Commit()
if err != nil {
log.Fatal(err)
}