ORM
(This is still in an alpha state)
V has a built-in ORM (object-relational mapping) which supports SQLite, MySQL and Postgres, but soon it will support MS SQL and Oracle.
V's ORM provides a number of benefits:
- One syntax for all SQL dialects. (Migrating between databases becomes much easier.)
- Queries are constructed using V's syntax. (There's no need to learn another syntax.)
- Safety. (All queries are automatically sanitised to prevent SQL injection.)
- Compile time checks. (This prevents typos which can only be caught during runtime.)
- Readability and simplicity. (You don't need to manually parse the results of a query and then manually construct objects from the parsed results.)
import db.sqlite
// sets a custom table name. Default is struct name (case-sensitive)
@[table: 'customers']
struct Customer {
id int @[primary; sql: serial] // a field named `id` of integer type must be the first field
name string
nr_orders int
country ?string
}
db := sqlite.connect('customers.db')!
// You can create tables from your struct declarations. For example the next query will issue SQL similar to this:
// CREATE TABLE IF NOT EXISTS `Customer` (
// `id` INTEGER PRIMARY KEY,
// `name` TEXT NOT NULL,
// `nr_orders` INTEGER NOT NULL,
// `country` TEXT
// )
sql db {
create table Customer
}!
// insert a new customer:
new_customer := Customer{
name: 'Bob'
country: 'uk'
nr_orders: 10
}
sql db {
insert new_customer into Customer
}!
us_customer := Customer{
name: 'Martin'
country: 'us'
nr_orders: 5
}
sql db {
insert us_customer into Customer
}!
none_country_customer := Customer{
name: 'Dennis'
country: none
nr_orders: 2
}
sql db {
insert none_country_customer into Customer
}!
// update a customer:
sql db {
update Customer set nr_orders = nr_orders + 1 where name == 'Bob'
}!
// select count(*) from customers
nr_customers := sql db {
select count from Customer
}!
println('number of all customers: ${nr_customers}')
// V's syntax can be used to build queries:
uk_customers := sql db {
select from Customer where country == 'uk' && nr_orders > 0
}!
println('We found a total of ${uk_customers.len} customers matching the query.')
for c in uk_customers {
println('customer: ${c.id}, ${c.name}, ${c.country}, ${c.nr_orders}')
}
none_country_customers := sql db {
select from Customer where country is none
}!
println('We found a total of ${none_country_customers.len} customers, with no country set.')
for c in none_country_customers {
println('customer: ${c.id}, ${c.name}, ${c.country}, ${c.nr_orders}')
}
// delete a customer
sql db {
delete from Customer where name == 'Bob'
}!
For more examples and the docs, see vlib/orm.