Inserting rows

In the code below, we initially import the table-mapping feature map.ts and the setup script init.ts, both of which were defined in the preceding step. The setup script executes a raw query that creates the necessary tables. Subsequently, we insert two customers, named "George" and "Harry", into the customer table, and this is achieved through calling db.customer.insert.

Next, we insert an array of two orders in the order table. Each order contains an orderDate, customer information, deliveryAddress, and lines for the order items. We use the customer constants "george" and "harry" from previous inserts. Observe that we don't pass in any primary keys. This is because all tables here have autoincremental keys.

The second argument to db.order.insert specifies a fetching strategy. This fetching strategy plays a critical role in determining the depth of the data retrieved from the database after insertion. The fetching strategy specifies which associated data should be retrieved and included in the resulting orders object.
In this case, the fetching strategy instructs the database to retrieve the customer, deliveryAddress, and lines for each order.

Without a fetching strategy, db.order.insert would only return the root level of each order. In that case you would only get the id, orderDate, and customerId for each order.

import map from './map';
const db = map.sqlite('demo.db');
import init from './init';

insertRows();

async function insertRows() {
  await init();

  const george = await db.customer.insert({
    name: 'George',
    balance: 177,
    isActive: true
  });

  const harry = await db.customer.insert({
    name: 'Harry',
    balance: 200,
    isActive: true
  });

  const orders = await db.order.insert([
    {
      orderDate: new Date(2022, 0, 11, 9, 24, 47),
      customer: george,
      deliveryAddress: {
        name: 'George',
        street: 'Node street 1',
        postalCode: '7059',
        postalPlace: 'Jakobsli',
        countryCode: 'NO'
      },
      lines: [
        { product: 'Bicycle', amount: 250 },
        { product: 'Small guitar', amount: 150 }
      ]
    },
    {
      customer: harry,
      orderDate: new Date(2021, 0, 11, 12, 22, 45),
      deliveryAddress: {
        name: 'Harry Potter',
        street: '4 Privet Drive, Little Whinging',
        postalCode: 'GU4',
        postalPlace: 'Surrey',
        countryCode: 'UK'
      },
      lines: [
        { product: 'Magic wand', amount: 300 }
      ]
    }
  ], {customer: true, deliveryAddress: true, lines: true}); //fetching strategy
}

Conflict resolution

By default, the strategy for inserting rows is set to an optimistic approach. In this case, if a row is being inserted with an already existing primary key, the database raises an exception.

Currently, there are three concurrency strategies:

• optimistic Raises an exception if another row was already inserted on that primary key.
• overwrite Overwrites the property, regardless of changes by others.
• skipOnConflict Silently avoids updating the property if another user has modified it in the interim.

The concurrency option can be set either for the whole table or individually for each column. In the example below, we've set the concurrency strategy on vendor table to overwrite except for the column balance which uses the skipOnConflictstrategy.

In this particular case, a row with id: 1 already exists, the name and isActive fields will be overwritten, but the balance will remain the same as in the original record, demonstrating the effectiveness of combining multiple concurrency strategies.

import map from './map';
const db = map.sqlite('demo.db');

insertRows();

async function insertRows() {

  db2 = db({
    vendor: {
      balance: {
        concurrency: 'skipOnConflict'
      },
      concurrency: 'overwrite'
    }
  });

  await db2.vendor.insert({
    id: 1,
    name: 'John',
    balance: 100,
    isActive: true
  });

  //this will overwrite all fields but balance
  const george = await db2.vendor.insert({
    id: 1,
    name: 'George',
    balance: 177,
        isActive: false
  });
  console.dir(george, {depth: Infinity});
  // {
  //   id: 1,
  //   name: 'George',
  //   balance: 100,
  //   isActive: false
  // }
}