Question: Multi-insert statement

Postgres supports something like: INSERT INTO foo(a,b) VALUES (q,r), (s,t) ...

How can I do this in node-postgres? Right now I’m using a transaction, and async.parallelLimit for individual INSERTs. But this seems rather inefficient, and it’s as I need it for a reasonably high-volume log – where every few seconds I need to insert quite a bit of data – performance matters.

So I’m wondering if there’s a better way. (And I happy to string concat my own query, but I don’t an escaping function exposed)

[kethinov]

The above needs a slight tweak in the middle to actually work:

var rows = [{
  name: 'Brian',
  age: 31
}, {
  name: 'Aaron',
  age: 29
}]

function buildStatement (insert, rows) {
  const params = []
  const chunks = []
  rows.forEach(row => {
    const valueClause = []
    Object.keys(row).forEach(p => {
      params.push(row[p])
      valueClause.push('$' + params.length)
    })
    chunks.push('(' + valueClause.join(', ') + ')')
  })
  return {
    text: insert + chunks.join(', '),
    values: params
  }
}

client.query(buildStatement('INSERT INTO foo(name, age) VALUES ', rows))

FYI for anyone reading the thread, buildStatement returns the following SQL:

{ statement: 'INSERT INTO foo(name, age) VALUES ($1, $2), ($3, $4)',
  params: [ 'Brian', 31, 'Aaron', 29 ] }

[brianc]

You can still do this with a prepared statement, you’ll just have to build up the parameters and append them all to the query…something like:

var rows = [{
  name: 'Brian',
  age: 31
}, {
  name: 'Aaron',
  age: 29
}]

var buildStatement = function(rows) {
  var params = []
  var chunks = []
  for(var i = 0; i < rows.lenght; i++) {
    var row = rows[i]
    var valuesClause = []
    params.push(row.name)
    valueClause.push('$' + params.length)
    params.push(row.age)
    valueClause.push('$' + params.length)
    chunks.push('(' + valueClause.join(', ') + ')')
  }
  return {
    text: 'INSERT INTO foo(name, age) VALUES ' + chunks.join(', '),
    values: params
  } 
}

client.query(buildStatement(rows))

Something like that. I wrote it off the top of my head. There are also a myriad of query builders for node which should help make this much easier.