Connecting to the database
Before diving into the application, let's take a quick look at how to connect to the database from your code. We will intialize a client and use it to make a simple, static query to the database, and log the result to the console.
Notice that the createClient function isn't being passed any connection details. With Gel, you do not need to come up with your own scheme for how to build the correct database connection credentials and worry about leaking them into your code. You simply use Gel "projects" for local development, and set the appropriate environment variables in your deployment environments, and the createClient function knows what to do!
import { createClient } from "gel";
const client = createClient();
async function main() {
console.log(await client.query("select 'Hello from Gel!';"));
}
main().then(
() => process.exit(0),
(err) => {
console.error(err);
process.exit(1);
}
);$
npx tsx test.ts[ 'Hello from Gel!' ]
With TypeScript, there are three ways to run a query: use a string EdgeQL query, use the queries generator to turn a string of EdgeQL into a TypeScript function, or use the query builder API to build queries dynamically in a type-safe manner. In this tutorial, you will use the TypeScript query builder API.
This query builder must be regenerated any time the schema changes, so a hook has been added to the gel.toml file to generate the query builder any time the schema is updated. Moving beyond this simple query, use the query builder API to insert a few Deck objects into the database, and then select them back.
import { createClient } from "gel"; import e from "@/dbschema/edgeql-js"; const client = createClient(); async function main() { console.log(await client.query("select 'Hello from Gel!';")); await e.insert(e.Deck, { name: "I am one" }).run(client); await e.insert(e.Deck, { name: "I am two" }).run(client); const decks = await e .select(e.Deck, () => ({ id: true, name: true, })) .run(client); console.table(decks); await e.delete(e.Deck).run(client); } main().then(
$
npx tsx test.ts[ 'Hello from Gel!' ] ┌─────────┬────────────────────────────────────────┬────────────┐ │ (index) │ id │ name │ ├─────────┼────────────────────────────────────────┼────────────┤ │ 0 │ 'f4cd3e6c-ea75-11ef-83ec-037350ea8a6e' │ 'I am one' │ │ 1 │ 'f4cf27ae-ea75-11ef-83ec-3f7b2fceab24' │ 'I am two' │ └─────────┴────────────────────────────────────────┴────────────┘
Now that you know how to connect to the database, you will see that we have provided an initialized Client object in the /lib/gel.ts module. Throughout the rest of the tutorial, you will import this Client object and use it to make queries.