querying.md

Querying Data

SencilloDB provides powerful querying capabilities, including MongoDB-like operators and relational population.

Basic Finding

You can find documents using a callback function:

const user = await db.transaction(tx => {
  return tx.find({
    collection: "users",
    callback: (user) => user.name === "Alex"
  });
});

Query Operators

Instead of a callback, you can use a filter object with operators.

Comparison Operators

• $eq: Equal to (implicit if no operator specified)
• $ne: Not equal to
• $gt: Greater than
• $gte: Greater than or equal to
• $lt: Less than
• $lte: Less than or equal to

// Find users older than 18
tx.findMany({
  collection: "users",
  filter: { age: { $gt: 18 } }
});

// Find users not named "Bob"
tx.findMany({
  collection: "users",
  filter: { name: { $ne: "Bob" } }
});

Array Operators

• $in: Value is in the specified array
• $nin: Value is NOT in the specified array

// Find users with role "admin" or "editor"
tx.findMany({
  collection: "users",
  filter: { role: { $in: ["admin", "editor"] } }
});

Evaluation Operators

• $regex: Match string against a regular expression pattern

// Find users whose name starts with "A"
tx.findMany({
  collection: "users",
  filter: { name: { $regex: "^A" } }
});

Relations & Population

SencilloDB allows you to reference documents in other collections and automatically "populate" them during a query.

Setup

Suppose you have users and posts.

// Create user
const user = tx.create({ collection: "users", data: { name: "Alice" } });

// Create post referencing user
tx.create({ 
  collection: "posts", 
  data: { title: "Hello World", authorId: user._id } 
});

Populating

Use the populate option to replace the ID with the actual document.

const posts = tx.findMany({
  collection: "posts",
  callback: () => true, // Return all posts
  populate: [
    { 
      field: "authorId",      // Field in 'posts' containing the ID
      collection: "users"     // Collection to search in
    }
  ]
});

console.log(posts[0].authorId); 
// Output: { _id: 1, name: "Alice" }

You can populate multiple fields by adding more objects to the populate array.