【发布时间】:2015-10-18 23:09:46
【问题描述】:
我正在尝试使用节点在 PostgreSQL 数据库上执行更新,但我得到一个 Error: Connection terminated 执行 UPDATE 操作。在以适当的异步方式处理连接时,我可能搞砸了,过早地终止了它们,但无法弄清楚如何正确执行。
很抱歉有一大堆代码,但它非常简单。
//main.js
var result = require('./processes.js');
result.check(function(message) {
console.log(message);
});
result.decrease(); //Throws an error.
//workers.js
var pg = require ('pg');
var fs = require('fs');
var db = JSON.parse(fs.readFileSync('../config.json', 'utf8')).db;
var querydb = require('./querydb.js');
var self = module.exports = {
check: function(callback) {
querydb.select("SELECT size FROM workers WHERE id = 1", function(results) {
callback(results[0].size);
});
},
increase: function() {
self.check(function(workers) {
querydb.update("UPDATE workers SET size = " + (workers + 1) + " WHERE id = 1");
});
},
decrease: function() {
self.check(function(workers) {
querydb.update("UPDATE workers SET size = " + (workers - 1) + " WHERE id = 1");
});
}
};
//querydb.js
var pg = require ('pg');
var fs = require('fs');
var db = JSON.parse(fs.readFileSync('../config.json', 'utf8')).db;
var select = function(statement, callback) {
pg.connect(db, function(err, client, done) {
var results = [];
//Handle errors
if(err) {
done();
console.log(err);
}
var query = client.query(statement);
//Stream results back
query.on('row', function(row) {
results.push(row);
});
//When all data is returned.
query.on('end', function() {
done();
callback(results);
client.end();
});
});
}
var update = function(statement) {
pg.connect(db, function(err, client, done) {
var results = [];
//Handle errors
if(err) {
done();
console.log(err);
}
var query = client.query(statement);
//When all data is returned.
query.on('end', function() {
done();
client.end();
});
});
}
module.exports = {
select: select,
update: update
};
【问题讨论】:
-
如果您改用pg-promise,您就不会对连接感到头疼,因为它们会被自动处理。
标签: sql node.js postgresql sql-update