A convenience wrapper around the pg module's Pool object.
npm install --save pgaconst pga = require('pga');
var db = pga({
user: 'postgres',
password: '',
database: 'postgres',
host: 'localhost',
port: 5432,
max: 10
});Closes the database connection. An alias for Pool.end.
db.close();Performs a series of parameterized queries in parallel over multiple connections from the underlying pool.
Query execution order is arbitrary, but the results are returned in the expected order.
If a single query results in an error, parallel will immediately execute the specified callback function with both the error and potentially a partial array of results from other successful queries. When returning a Promise, one error among any of the queries will result in the Promise being rejected.
parallel is provided as a means of efficiently performing multiple SELECT queries at once rather than one after the other in sequence. Do not use parallel to execute grouped SQL queries that may potentially alter the database- use transact instead!
// Parallelized queries with a callback function.
db.parallel([
'SELECT COUNT(*) FROM test;',
{ text: 'SELECT * FROM test WHERE id = $1::int;', values: [ 1 ] },
'SELECT * FROM test;'
], function(error, results) {
if (error) {
return console.error(error);
}
console.log(results);
});
// Parallelized queries that return a Promise object.
db.parallel([
'SELECT COUNT(*) FROM test;',
{ text: 'SELECT * FROM test WHERE id = $1::int;', values: [ 1 ] },
'SELECT * FROM test;'
]).then(function(results) {
console.log(results);
}).catch(function(error) {
console.error(error);
});pga also accepts comma-separated queries and optional callback functions for parallel queries if passing in an array is too unwieldy:
db.parallel(
'SELECT COUNT(*) FROM test;',
{ text: 'SELECT * FROM test WHERE id = $1::int;', values: [ 1 ] },
'SELECT * FROM test;',
function(error, results) {
if (error) {
return console.error(error);
}
console.log(results);
});Performs a single parameterized query. An alias for Pool.query.
// A regular query with a callback function.
db.query('SELECT * FROM test;', function(error, result) {
if (error) {
return console.error(error);
}
console.log(result.rows);
});
// A regular query with a parameter and callback function.
db.query('SELECT * FROM test WHERE id = $1::int;', [ 1 ], function(error, result) {
if (error) {
return console.error(error);
}
console.log(result.rows);
});
// A regular query that returns a Promise object.
db.query('SELECT * FROM test;').then(function(result) {
console.log(result.rows);
}).catch(function(error) {
console.error(error);
});
// A regular query with a parameter that returns a Promise object.
db.query('SELECT * FROM test WHERE id = $1::int;', [ 1 ]).then(function(result) {
console.log(result.rows);
}).catch(function(error) {
console.error(error);
});Performs a database transaction on an array of parameterized queries.
// A transaction with a callback function.
db.transact([
'SELECT COUNT(*) FROM test;',
{ text: 'SELECT * FROM test WHERE id = $1::int;', values: [ 1 ] },
{ text: 'INSERT INTO test (name) VALUES ($1:text);', values: [ 'Name!' ] },
'SELECT COUNT(*) FROM test;'
], function(error, results) {
if (error) {
return console.error(error);
}
console.log(results);
});
// A transaction that returns a Promise object.
db.transact([
'SELECT COUNT(*) FROM test;',
{ text: 'SELECT * FROM test WHERE id = $1::int;', values: [ 1 ] },
{ text: 'INSERT INTO test (name) VALUES ($1:text);', values: [ 'Name!' ] },
'SELECT COUNT(*) FROM test;'
]).then(function(results) {
console.log(results);
}).catch(function(error) {
console.error(error);
});pga also accepts comma-separated queries and optional callback functions for transactions if passing in an array is too unwieldy:
db.transact(
'SELECT COUNT(*) FROM test;',
{ text: 'INSERT INTO test (name) VALUES ($1:text);', values: [ 'Name!' ] },
'SELECT COUNT(*) FROM test;',
function(error, results) {
if (error) {
return console.error(error);
}
console.log(results);
});- pga-sql for cleaner parameterized queries
- pga-pubsub for PostgreSQL LISTEN/NOTIFY