FAQ

Thanks to g40

1. how do I know what values are on the row object ?

The row object has properties which align to the column names returned from the query.

Given a table users with columns 'name' and 'age' doing select * from users would return you a result object with an array of row objects. Each row object would have the properties name and age. Example:

client.query('SELECT * FROM users`, function(err, result) {
  console.log('name: %s and age: %d', result.rows[0].name, result.rows[0].age);
  //since the row object is just a hash, it can be accessed also as follows
  console.log('name: %s and age: %d', result.rows[0]['name'], result.rows[0]['age']);
});

2. can I iterate across the columns in the recordset to dynamically display column names ?

Why, yes. Yes you can.

client.query(..., function(err, result) { 
  var firstRow = result.rows[0];
  for(var columnName in firstRow) {
    console.log('column "%s" has a value of "%j"', columnName, firstRow[columnName]);
  }
});

3. Assuming a recordset is enumerated using the array accessor style used in 1, can we get the column names in the same fashion, i.e. is there a result.rows[i].columnName property?

Not currently. It would be helpful to access the column values by column name or index position, but it's not part of the node-postgres api for now.

4. How do you get the count of columns in the result set ?

pg.query(..., function(err, result) {
  var columnCount = Object.keys(result.rows[0]).length;
});

5. If pg returns query data in JSON format, for web service applications, it would make sense to return that directly to the client. If this assumption is correct what is the most efficient method?

http.createServer(function(req, res) {
  //NOTE: pg connection boilerplate not present
  pg.query(..., function(err, result) {
    //NOTE: error handling not present
    var json = JSON.stringify(result.rows);
    res.writeHead(200, {'content-type':'application/json', 'content-length':json.length}); 
    res.end(json);
  });
})

Thank you Brian. pg is excellent.