alasql/src/64altertable.js

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

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

// ALTER TABLE table1 RENAME TO table2
yy.AlterTable = function (params) { return yy.extend(this, params); }
yy.AlterTable.prototype.toString = function() {
	var s = 'ALTER TABLE '+this.table.toString(); 
	if(this.renameto) s += ' RENAME TO '+this.renameto;
	return s;
}

yy.AlterTable.prototype.execute = function (databaseid, params, cb) {
	var db = alasql.databases[databaseid];
	db.dbversion = Date.now();

	if(this.renameto) {
		var oldtableid = this.table.tableid;
		var newtableid = this.renameto;
			var res = 1;
			if(db.tables[newtableid]) {
				throw new Error("Can not rename a table '"+oldtableid+"' to '"
					+newtableid+"', because the table with this name already exists");
			} else if(newtableid == oldtableid) {
				throw new Error("Can not rename a table '"+oldtableid+"' to itself");
			} else {
				db.tables[newtableid] = db.tables[oldtableid];
				delete db.tables[oldtableid];
				res = 1;
			};
			if(cb) cb(res)
			return res;
	} else if(this.addcolumn) {
		var db = alasql.databases[this.table.databaseid || databaseid];
		db.dbversion++;
		var tableid = this.table.tableid;
		var table = db.tables[tableid];
		var columnid = this.addcolumn.columnid;
		if(table.xcolumns[columnid]) {
			throw new Error('Cannot add column "'+columnid+'", because it already exists in the table "'+tableid+'"');
		}

		var col = {
			columnid:columnid,
			dbtypeid:this.dbtypeid,
			dbsize:this.dbsize,
			dbprecision:this.dbprecision,
			dbenum:this.dbenum,
			defaultfns: null // TODO defaultfns!!!
		};

		var defaultfn = function(){};

		table.columns.push(col);
		table.xcolumns[columnid] = col;

		for(var i=0, ilen=table.data.length; i<ilen; i++) {
//				console.log(table.data[i][columnid]);
			table.data[i][columnid] = defaultfn();
		}

		// TODO
		return 1;
	} else if(this.modifycolumn) {
		var db = alasql.databases[this.table.databaseid || databaseid];
		db.dbversion++;
		var tableid = this.table.tableid;
		var table = db.tables[tableid];
		var columnid = this.modifycolumn.columnid;

		if(!table.xcolumns[columnid]) {
			throw new Error('Cannot modify column "'+columnid+'", because it was not found in the table "'+tableid+'"');
		}

		var col = table.xcolumns[columnid];
		col.dbtypeid = this.dbtypeid;
		col.dbsize = this.dbsize;
		col.dbprecision = this.dbprecision;
		col.dbenum = this.dbenum;


		// TODO
		return 1;
	} else if(this.renamecolumn) {
		var db = alasql.databases[this.table.databaseid || databaseid];
		db.dbversion++;

		var tableid = this.table.tableid;
		var table = db.tables[tableid];
		var columnid = this.renamecolumn;
		var tocolumnid = this.to;

		var col;
		if(!table.xcolumns[columnid]) {
			throw new Error('Column "'+columnid+'" is not found in the table "'+tableid+'"');
		}
		if(table.xcolumns[tocolumnid]) {
			throw new Error('Column "'+tocolumnid+'" already exists in the table "'+tableid+'"');
		}

		if(columnid != tocolumnid) {
			for(var j=0; j<table.columns.length; j++) {
				if(table.columns[j].columnid == columnid) {
					table.columns[j].columnid = tocolumnid;
				}
			};

			table.xcolumns[tocolumnid]=table.xcolumns[columnid];
			delete table.xcolumns[columnid];

			for(var i=0, ilen=table.data.length; i<ilen; i++) {
//				console.log(table.data[i][columnid]);
				table.data[i][tocolumnid] = table.data[i][columnid];
				delete table.data[i][columnid];
			}
			return table.data.length;
		}
		else return 0;
	} else if(this.dropcolumn) {
		var db = alasql.databases[this.table.databaseid || databaseid];
		db.dbversion++;
		var tableid = this.table.tableid;
		var table = db.tables[tableid];
		var columnid = this.dropcolumn;

		var found = false;
		for(var j=0; j<table.columns.length; j++) {
			if(table.columns[j].columnid == columnid) {
				found = true;
				table.columns.splice(j,1);
				break;
			}
		};

		if(!found) {
			throw new Error('Cannot drop column "'+columnid+'", because it was not found in the table "'+tableid+'"');
		}

		delete table.xcolumns[columnid];

		for(var i=0, ilen=table.data.length; i<ilen; i++) {
			delete table.data[i][columnid];
		}
		return table.data.length;
	} else {
		throw Error('Unknown ALTER TABLE method');
	}

};