Go sqlite3
last modified April 11, 2024
In this article we show how to work with sqlite3 database in Golang. The examples perform basic database operations.
$ go version go version go1.22.2 linux/amd64
We use Go version 1.22.2.
SQLite is an embedded relational database engine. The documentation calls it a self-contained, serverless, zero-configuration and transactional SQL database engine. It is very popular with hundreds of millions copies worldwide in use today.
Go has the sql package which provides a generic interface around
SQL (or SQL-like) databases. The sql package must be used in conjunction with a
database driver.
Creating SQLite database
We can use the sqlite3 command line tool to create a database and
query for data.
$ sudo apt install sqlite3
We install the tool.
$ sqlite3 test.db SQLite version 3.37.2 2022-01-06 13:25:41 Enter ".help" for usage hints. sqlite>
We provide a parameter to the sqlite3 tool; the
test.db is the database name. It is a file on our disk. If it is
present, it is opened. If not, it is created.
sqlite> .tables sqlite> .exit $ ls test.db
The .tables command gives a list of tables in the test.db
database. There are currently no tables. The .exit command
terminates the interactive session of the sqlite3 command line tool.
The ls command shows the contents of the current working
directory. We can see the test.db file. All data will be stored
in this single file.
Go sqlite3 version
In the first example, we print the version of sqlite3.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", ":memory:")
if err != nil {
log.Fatal(err)
}
defer db.Close()
var version string
err = db.QueryRow("SELECT SQLITE_VERSION()").Scan(&version)
if err != nil {
log.Fatal(err)
}
fmt.Println(version)
}
The program returns the version of sqlite3. The version is determined by
executing the SELECT SQLITE_VERSION() statement.
_ "github.com/mattn/go-sqlite3"
When a package is imported prefixed with a blank identifier, the init function of the package is called. The function registers the driver.
db, err := sql.Open("sqlite3", ":memory:")
With sql.Open, we open a database specified by its database driver
name and a driver-specific data source name. In our case, we connect to the
in-memory database.
defer db.Close()
The Close function closes the database and prevents new queries
from starting.
err = db.QueryRow("SELECT SQLITE_VERSION()").Scan(&version)
The QueryRow executes a query that is expected to return at most
one row. The Scan function copies the column from the matched row
into the version variable.
$ go run main.go 3.38.5
Go sqlite3 Exec
The Exec function executes a query without returning any rows.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", "test.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
sts := `
DROP TABLE IF EXISTS cars;
CREATE TABLE cars(id INTEGER PRIMARY KEY, name TEXT, price INT);
INSERT INTO cars(name, price) VALUES('Audi',52642);
INSERT INTO cars(name, price) VALUES('Mercedes',57127);
INSERT INTO cars(name, price) VALUES('Skoda',9000);
INSERT INTO cars(name, price) VALUES('Volvo',29000);
INSERT INTO cars(name, price) VALUES('Bentley',350000);
INSERT INTO cars(name, price) VALUES('Citroen',21000);
INSERT INTO cars(name, price) VALUES('Hummer',41400);
INSERT INTO cars(name, price) VALUES('Volkswagen',21600);
`
_, err = db.Exec(sts)
if err != nil {
log.Fatal(err)
}
fmt.Println("table cars created")
}
In the example, we create a new table.
db, err := sql.Open("sqlite3", "test.db")
We create a new file database.
sts := `
DROP TABLE IF EXISTS cars;
CREATE TABLE cars(id INTEGER PRIMARY KEY, name TEXT, price INT);
INSERT INTO cars(name, price) VALUES('Audi',52642);
INSERT INTO cars(name, price) VALUES('Mercedes',57127);
INSERT INTO cars(name, price) VALUES('Skoda',9000);
INSERT INTO cars(name, price) VALUES('Volvo',29000);
INSERT INTO cars(name, price) VALUES('Bentley',350000);
INSERT INTO cars(name, price) VALUES('Citroen',21000);
INSERT INTO cars(name, price) VALUES('Hummer',41400);
INSERT INTO cars(name, price) VALUES('Volkswagen',21600);
`
These are SQL statements to create a new table.
_, err = db.Exec(sts)
The statements are executed with Exec.
Go sqlite3 select all rows with Query
The Query executes a query that returns rows, typically a SELECT.
The optional arguments are for any placeholder parameters in the query.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", "test.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
rows, err := db.Query("SELECT * FROM cars")
if err != nil {
log.Fatal(err)
}
defer rows.Close()
for rows.Next() {
var id int
var name string
var price int
err = rows.Scan(&id, &name, &price)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%d %s %d\n", id, name, price)
}
}
The example selects all rows from the cars table.
rows, err := db.Query("SELECT * FROM cars")
This is the SQL to select all rows.
for rows.Next() {
The Next prepares the next result row for reading with the
Scan method. It returns true on success, or false if there is no
next result row or an error happened while preparing it.
err = rows.Scan(&id, &name, &price)
We read the row into the variables.
fmt.Printf("%d %s %d\n", id, name, price)
The current row is printed.
$ go run main.go 1 Audi 52642 2 Mercedes 57127 3 Skoda 9000 4 Volvo 29000 5 Bentley 350000 6 Citroen 21000 7 Hummer 41400 8 Volkswagen 21600
Go sqlite3 prepared statement
With prepared statements, we use placeholders instead of directly writing the values into the statements. Prepared statements increase security and performance of database operations.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", "test.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
stm, err := db.Prepare("SELECT * FROM cars WHERE id = ?")
if err != nil {
log.Fatal(err)
}
defer stm.Close()
var id int
var name string
var price int
cid := 3
err = stm.QueryRow(cid).Scan(&id, &name, &price)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%d %s %d\n", id, name, price)
}
We use a prepared statement to select a specific row.
stm, err := db.Prepare("SELECT * FROM cars WHERE id = ?")
The Prepare function creates a prepared statement for later queries
or executions. The placeholder ? is later filled with value.
err = stm.QueryRow(cid).Scan(&id, &name, &price)
The value passed to the QueryRow function maps to the placeholder.
The Scan function copies the columns from the matched row into the
variables.
$ go run main.go 3 Skoda 9000
It is also possible to do the prepared statement in one step go with
QueryRow.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", "test.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
cid := 3
var id int
var name string
var price int
row := db.QueryRow("SELECT * FROM cars WHERE id = ?", cid)
err = row.Scan(&id, &name, &price)
if err != nil {
log.Fatal(err)
}
fmt.Printf("%d %s %d\n", id, name, price)
}
The example creates a prepared statement; this time with QueryRow.
Go sqlite3 affected rows
The RowsAffected returns the number of rows affected by an
update, insert, or delete statements.
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
)
func main() {
db, err := sql.Open("sqlite3", "test.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
res, err := db.Exec("DELETE FROM cars WHERE id IN (1, 2, 3)")
if err != nil {
log.Fatal(err)
}
n, err := res.RowsAffected()
if err != nil {
log.Fatal(err)
}
fmt.Printf("The statement has affected %d rows\n", n)
}
In the code example, we delete three rows with a DELETE SQL statement. Then
we print the number of deleted rows with RowsAffected.
$ go run main.go The statement has affected 3 rows
Source
In this article we have worked with sqlite3 in Go.
Author
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