Tiny but powerful Promise based PostgreSQL client for node.js
designed for easy use with ES7 async/await.
Based on node-postgres (known as pg in npm registry).
Can use pg or native pg-native backend.
import PgAsync, {SQL} from 'pg-async';
// using default connection
const pgAsync = new PgAsync();
const userTable = 'user';
const sqlUserByLogin = (login) => SQL`
select id
from $ID${userTable}
where login = ${login}
`;
async function setPassword(login, newPwd) {
const userId = await pgAsync.value(sqlUserByLogin(login));
// userId is guaranted here,
// pgAsync.value requires query yielding exactly one row with one column.
await pgAsync.query(SQL`
update $ID${userTable} set
passwd = ${newPwd}
where userId = ${userId}
`);
}$ npm install --save pg-async
new PgAsync([connectionOptions], [driver])- The default export of
pg-asyncisPgAsyncclass which let you configure connection options - Connection options defaults to
pg.defaults - Optional
driverlet you choose underlying library - To use the native bindings you must
npm install --save pg-native
import PgAsync from 'pg-async';
// using default connection
const pgAsync = new PgAsync();
// using connection string
const pgAsync = new PgAsync({connectionString: 'postgres://user:secret@host:port/database'});
// using connection object
const pgAsync = new PgAsync({user, password, host, port, database, ...});
// using default for current user, with native driver
// install pg-native package manually
const pgAsync = new PgAsync(null, 'native');
const pgAsync = new PgAsync(null, require('pg').native);- Execute SQL and return
Resultobject from underlyingpglibrary - Interesting properties on
Resultobject are:rowCountNumber – returned rowsoidNumber – Postgres oidrowsArray – Actual result ofpgAsync.rows()rowAsArrayBooleanfieldsArray of:nameString – name or alias of columntableIDNumber – oid of table or 0columnIDNumber – index of column in table or 0dataTypeIDNumber – oid of data typedataTypeSizeNumber – size in bytes od colum, -1 for variable length-
dataTypeModifierNumber
- Execute SQL and return array of key/value objects (
result.rows)
- Execute SQL and return single key/value object. If query yields more than one or none rows, promise will be rejected.
- Rejected promise throw exception at
awaitlocation.
- Same as row, but query must yields single column in single row, otherwise throws.
- Execute multiple queries in sequence on same connection. This is handy for transactions.
asyncFunchere has signatureasync (client, pgClient) => { ... }- provided
clienthas async methods:query,rows,row,valueas abovequeryArgs,rowsArgs,rowArgs,valueArgsas abovestartTransaction,commit,rollback- start new transaction manually. UsepgAsync.transactionwhen possible
clientitself is shorthand forquery
Transaction is similar to connect but automatically start and commit transaction,
rollback on throwen error
Example:
const pgAsync = new PgAsync();
function moveMoney(fromAccount, toAccount, amount) {
return pgAsync.transaction(async (client) => {
let movementFrom, movementTo, movementId;
const sql = `
INSERT INTO bank_account (account, amount)
VALUES ($1, $2)
RETURNING id
`;
movementFrom = await client.value(sql, [fromAccount, -amount]);
movementTo = await client.value(sql, [toAccount, amount]);
return {movementFrom, movementTo}
});
}
async function doTheWork() {
// ...
try {
const result = await moveMoney('alice', 'bob', 19.95);
// transaction is commited
} catch (err) {
// transaction is rollbacked
}
// ...
}- Get unwrapped
pg.Clientcallback based instance.
You should not call this method unless you know what are you doing. - Client must be returned to pool manually by calling
done()
- Disconnects all idle clients within all active pools, and has all client pools terminate.
See
pool.end() - This actually terminates all connections on driver used by Pg instance
-
pgdriver support -
pg.nativedriver support -
debug— Enable debugging withDEBUG="pg-async"environment variable - Transaction API wrapper - Postgres does not support nested transactions
- Template tag SQL formatting
- Transaction
SAVEPOINTsupport - Cursor API wrapper
If you miss something, don't be shy, just
open new issue!
It will be nice if you label your issue with prefix [bug] [doc] [question] [typo]
etc.
Copyright (c) 2016 Pavel Lang ([email protected])
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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