postgresql with promises and strict types and returning size of results
PG Promise/A+ in the strict way:
- The same functions, with the same name and same retunrs that in PG, but without callbacks
- covers 100% by test.
- 100% coded in typescript
- No reimplement nothing that PG does
- Some additions for comfort
$ npm install pg-promise-strict
var pg = require('pg-promise-strict');
var conOpts = {
user: 'test_user',
password: 'test_pass',
database: 'test_db',
host: 'localhost',
port: 5432
};
pg.connect(conOpts).then(function(client){
return client.query('select * from table').fetchAll().then(function(result){
for(var i=0; i<result.rowCount; i++){
console.log('row',i,result.rows[i]);
}
client.done();
});
}).catch(function(err){
console.log('ERROR',err);
});
The first easy example. One simple query that returns all rows. Example based in PG
var pg = require('pg-promise-strict');
var conString = "postgres://username:password@localhost/database";
try{
var client = await pg.connect(conString)
var result = await client.query('SELECT $1::int AS number', ['1']).fetchAll();
console.log(result.rows[0].number);
}catch(err){
console.error('error fetching client from pool or running query', err);
};
In this example you see:
- async calls
- parameters passed to libpq in the query function
- the fetchAll function that convirms that you want all rows.
Corresponds to calls to PG direct client instance
var pg = require('pg-promise-strict');
var conString = "postgres://username:password@localhost/database";
var client = new pg.Client(conString);
try{
await client.connect();
var result = await client.query('SELECT NOW() AS "theTime"').fetchAll();
console.log(result.rows[0].theTime);
console.log(row.name);
client.done();
}catch(err){
console.error('error connecting or running query', err);
});
Corresponds to calls to PG.query without callback. In PG documentation Brian C says do not provide callback function for large result sets unless you're okay with loading the entire result set into memory
This is the way for process data row by row
var client = await pg.connect({user: 'brianc', database: 'test'});
await client.query("SELECT name FROM users").onRow(function(row){
console.log(row.name);
});
client.done();
console.log('ready.');
In this example you see:
- the on-row callback
- the await until the query has finished
In the examples
directory the create_db.sql
script can be used to create de test database.
In the same directory there are the example slightly modified.
Clone the repository and install the developer dependencies in then normal way. You must provide a postgresql-9.3 instalation for create a test_db. Then you can test pg-promise-strict
$ git clone git://github.com/codenautas/pg-promise-strict.git pg-promise-strict
$ cd pg-promise-strict
$ npm install
$ psql --file test/create_db.sql
$ npm test