alasql/src/74update.js

AlaSQL.js - JavaScript SQL database library for relational and graph data manipulation with support of localStorage, IndexedDB, and Excel

/*
//
// UPDATE for Alasql.js
// Date: 03.11.2014
// (c) 2014, Andrey Gershun
//
*/

yy.Update = function (params) { return yy.extend(this, params); }
yy.Update.prototype.toString = function() {
	var s = 'UPDATE '+this.table.toString();
	if(this.columns) s += ' SET '+this.columns.toString();
	if(this.where) s += ' WHERE '+this.where.toString();
	return s;
}


yy.SetColumn = function (params) { return yy.extend(this, params); }
yy.SetColumn.prototype.toString = function() {
	return this.column.toString() + '='+this.expression.toString();
}

yy.Update.prototype.compile = function (databaseid) {
//	console.log(this);
	databaseid = this.table.databaseid || databaseid;
	var tableid = this.table.tableid;
	
	if(this.where) {
		var wherefn = new Function('r,params,alasql','return '+this.where.toJavaScript('r',''));
	};

	// Construct update function
	var s = '';
	this.columns.forEach(function(col){
		s += 'r[\''+col.column.columnid+'\']='+col.expression.toJavaScript('r','')+';'; 
	});
//	console.log('updatefn',s);
	var assignfn = new Function('r,params,alasql',s);

	var statement = function(params, cb) {
		var db = alasql.databases[databaseid];


//		console.log(db.engineid);
//		console.log(db.engineid && alasql.engines[db.engineid].updateTable);
		if(db.engineid && alasql.engines[db.engineid].updateTable) {
//			console.log('updateTable');
			return alasql.engines[db.engineid].updateTable(databaseid, tableid, assignfn, wherefn, params, cb);
		}

		if(alasql.options.autocommit && db.engineid) {
			alasql.engines[db.engineid].loadTableData(databaseid,tableid);
		}

		var table = db.tables[tableid];
		if(!table) {
			throw new Error("Table '"+tableid+"' not exists")
		}
//		table.dirty = true;
		var numrows = 0;
		for(var i=0, ilen=table.data.length; i<ilen; i++) {
			if(!wherefn || wherefn(table.data[i], params,alasql) ) {
				if(table.update) {
					table.update(assignfn, i, params);
				} else {
					assignfn(table.data[i], params,alasql);
				}
				numrows++;
			}
		};

		if(alasql.options.autocommit && db.engineid) {
			alasql.engines[db.engineid].saveTableData(databaseid,tableid);
		}

		if(cb) cb(numrows);
		return numrows;
	};
	return statement;
};

yy.Update.prototype.execute = function (databaseid, params, cb) {
	return this.compile(databaseid)(params,cb);
}