//基于json数据格式实现的简单数据库——jsonDB
//https://www.cnblogs.com/cynchanpin/p/7068151.html //已在github上建立项目：https://github.com/ThinkerCodeChina/jsonDB /** +----------------------------------------- * jsonDB 基于json数据格式构建的数据模型 +----------------------------------------- * @description 对json数据检索，删除，查询和更新 * @author 戚银(web程序员) [email protected] * @date 2014年6月28日 * @version 0.1 * @blog http://blog.csdn.net/thinkercode/ +----------------------------------------- * 简单介绍： * jsonDB是js的一个类库，是基于json数据格式构建的数据 * 模型实现对json数据增删改查。 jsonDB的构建源自于HTML5 * 本地存储的一个应用需求，能够通过sql对json数据进行增 * 删改查，同一时候该类库提供强大的where检索条件，数据排序， * limit查询条件限制等数据库基本功能。 通过jsonDB能够轻 * 松维护一个库/表或多个库/表。而无需额外实现json的数据 * 的维护等，在该类库完好以后为简化sql操作，基于jsonDB核 * 心模块扩展了连贯操作模型，简化对jsonDB的操作以及sql语 * 句出错的概率。 +----------------------------------------- * 当前版本号的不足： * 1.无法支持查询字段运算 * 2.不支持对没有选取的查询字段排序 * 3.仅仅支持单个字段排序，无法进行组合排序操作 * 4.update、delete语句不支持order by子句。导致limit子句功能弱化 * 5.编写where条件是必须使用()包括where条件 * 6.无法选取深层次的字段作为返回字段 * 7.没有错误或异常解决方式 * 8.不支持外部扩展 +----------------------------------------- * jsonDB的使用： * jsonDB会提供一个具体的使用手冊，当中包括大量演示样例 * jsonDB还有非常多能够使用的技巧并没有一一包括在手冊中 * 期望强大的网友一起挖掘jsonDB的潜在使用技巧。并分享给大家 * 假设使用中发现问题能够随时发送邮件，或者通过博客留言等方式一起探讨 * 同一时候鉴于自己实力有限，期望发动网友一起扩展jsonDB。 * 能在未来前端应用中奉献一份力量 +----------------------------------------- */ (function(window,undefined){ _jsonDB = window.jsonDB, _history = null, DBCore = {}, Database = {}, DBExpand = {}; /** * [jsonDB 初始化模型。支持定义本地数据库和数据表] * @param mixed data 数据 * @param string dbName 数据库名字 * @return jsonDB */ var jsonDB = function(data,dbName){ //创建数据库或者数据表 if(data){ dbName = dbName || 'json_db'; eval('Database.'+ dbName +'= data'); } return jsonDB.fn.init(); } jsonDB.fn = jsonDB.prototype = { //初始化插件 init : function (alias){ if(alias){ _history = window[alias]; window[alias] = jsonDB(); } return this; }, query : function(sql){ var type = sql.match(/^(\w+)/); switch(type[0]){ case 'select' : case 'delete' : case 'update' : return eval('DBCore.fn.'+ type[0] +'(sql+" ")'); break; default : return false; break; } }, insert : function(data,dbName){ if(data){ dbName = dbName || 'json_db'; eval('Database.'+ dbName +'.push(data)'); } return this; }, findAll : function(dbName){ if(dbName){ return eval('Database.'+ dbName); } return Database; } }; /** * [DBExpand 数据库核心功能扩展] */ DBExpand = DBExpand.prototype = { sqlParam : { fields : '*', table : 'json_db', where : null, order : null, limit : null, }, add : function(data){ return this.insert(data,this.sqlParam.table); }, select : function(){ var sql = 'select '+this.sqlParam.fields+' from '+this.sqlParam.table; if(this.sqlParam.where){ sql += ' where '+this.sqlParam.where; } if(this.sqlParam.order){ sql += ' order by '+this.sqlParam.order; } if(this.sqlParam.limit){ sql += ' limit '+this.sqlParam.limit; } this.clear(); return this.query(sql); }, update : function(data){ if(data.length<1){ return false; } var sql = 'update '+this.sqlParam.table+' set '+data; if(this.sqlParam.where){ sql += ' where '+this.sqlParam.where; } if(this.sqlParam.limit){ sql += ' limit '+this.sqlParam.limit; } this.clear(); return this.query(sql); }, delete : function(){ if(this.sqlParam.where.length<1){ return false; } var sql = 'delete from '+this.sqlParam.table; if(this.sqlParam.where){ sql += ' where '+this.sqlParam.where; } if(this.sqlParam.limit){ sql += ' limit '+this.sqlParam.limit; } this.clear(); return this.query(sql); }, drop : function(dbName){ //创建数据库或者数据表 if(data){ dbName = dbName || 'json_db'; eval('Database.'+ dbName +'= null'); } return this; }, field : function(fields){ if(typeof fields == 'object'){ this.sqlParam.fields = fields.join(','); }else{ this.sqlParam.fields = fields; } return this; }, table : function(table){ this.sqlParam.table = table; return this; }, where : function(where){ this.sqlParam.where = '('+where+')'; return this; }, order : function(order){ this.sqlParam.order = order; return this; }, limit : function(limit){ this.sqlParam.limit = limit; return this; }, clear : function(){ this.sqlParam.fields = '*'; this.sqlParam.where = null; this.sqlParam.order = null; this.sqlParam.limit = null; } } /** * [DBCore 数据库核心] */ DBCore.fn = DBCore.prototype = { SqlRegExp : { fields: '([a-z0-9_\\,\\.\\s\\*]*?\\s+)', from : '(from\\s+([a-z0-9_\\.]+)\\s*)?', where : '(?:where\\s+(\\(.*\\))\\s*)? ', order : '(?:order\\s+by\\s+([a-z0-9_\\,\\.]+))? \\s+(asc|desc|ascnum|descnum)?\\s*', limit : '(?:limit\\s+([0-9\\,]+))?', set : '(set\\s+(.*?)\\s+)', table : '(([a-z0-9_\\.]*?)\\s*)?', }, select : function(sql){ var params = {fields:["*"], from:"json_db", where:"", orderby:[], order: "asc", limit:[]}, SqlRegExp = this.SqlRegExp, reg = '^(select)\\s+'+SqlRegExp.fields + SqlRegExp.from + SqlRegExp.where + SqlRegExp.order + SqlRegExp.limit, sqlReg = new RegExp(reg,'i'), sqlFields = sql.match(sqlReg), options = { fields: sqlFields[2].replace(' ','').split(','), from: (sqlFields[4] == undefined) ? 'json_db' : sqlFields[4], where: (sqlFields[5] == undefined) ? "true" : sqlFields[5].replace(/([^\>\<\!\=])=([^\>\<\!\=])/gi,'$1 == $2').replace(/\sand\s/gi,' && ').replace(/\sor\s/gi,' || ').replace(/`/gi,''), orderby: (sqlFields[6] == undefined) ? []:sqlFields[6].replace(' ','').split(','), order: (sqlFields[7] == undefined) ? "asc" : sqlFields[7], limit: (sqlFields[8] == undefined) ? [] : sqlFields[8].replace(' ','').split(',') }; for(i in options){ params[i] = options[i]; } var result = []; result = this.filter(params,function(data){ if(options.fields.length == 0 || options.fields[0] == "*"){ return data; } var result = {}; for(var i in options.fields){ result[options.fields[i]] = data[options.fields[i]]; } return result; }); result = this.orderBy(result,options); result = this.limit(result,options); return result; }, update : function(sql){ var params = {from:"json_db", where:"", limit:[], set:[]}, SqlRegExp = this.SqlRegExp, reg = '^(update)\\s+'+ SqlRegExp.table + SqlRegExp.set + SqlRegExp.where + SqlRegExp.limit, sqlReg = new RegExp(reg,'i'), sqlFields = sql.match(sqlReg), options = { from: (sqlFields[3] == undefined) ? 'json_db' : sqlFields[3], set: (sqlFields[5] == undefined) ? [] : sqlFields[5].replace(' ','').split(','), where: (sqlFields[6] == undefined) ? "true" : sqlFields[6].replace(/([^\>\<\!\=])=([^\>\<\!\=])/gi,'$1 == $2').replace(/\sand\s/gi,' && ').replace(/\sor\s/gi,' || ').replace(/`/gi,''), limit: (sqlFields[7] == undefined) ? [] : sqlFields[7].replace(' ','').split(',') }; for(i in options){ params[i] = options[i]; } var jsonData = eval('Database.' + options.from), tally = 0, extent = this.extent(params), setLen = options.set.length, affected_rows = 0; if(setLen<1){ return false; } options.where = options.where || "true"; for(var i in jsonData){ with(jsonData[i]){ if(eval(options.where)){ if(affected_rows >= extent.start && tally < extent.stop){ for(var j=0;j<setLen;++j){ eval(options.set[j]); } ++tally; }else if(tally == extent.stop){ return tally; } ++affected_rows; } } } return tally; }, delete : function(sql){ var params = {from:"json_db", where:"", limit:[]}, SqlRegExp = this.SqlRegExp, reg = '^(delete)\\s+'+ SqlRegExp.from + SqlRegExp.where + SqlRegExp.limit, sqlReg = new RegExp(reg,'i'), sqlFields = sql.match(sqlReg), options = { from: (sqlFields[3] == undefined) ? 'json_db' : sqlFields[3], where: (sqlFields[4] == undefined) ? "true" : sqlFields[4].replace(/([^\>\<\!\=])=([^\>\<\!\=])/gi,'$1 == $2').replace(/\sand\s/gi,' && ').replace(/\sor\s/gi,' || ').replace(/`/gi,''), limit: (sqlFields[5] == undefined) ? [] : sqlFields[5].replace(' ','').split(',') }; for(i in options){ params[i] = options[i]; } var jsonData = eval('Database.' + options.from + '.concat()'), tally = 0, extent = this.extent(params), affected_rows = 0; options.where = options.where || "true"; for(var i in jsonData){ with(jsonData[i]){ if(eval(options.where)){ if(affected_rows >= extent.start && tally < extent.stop){ eval('Database.'+options.from+'.splice(i-tally,1)'); ++tally; }else if(tally == extent.stop){ return tally; } ++affected_rows; } } } return tally; }, filter : function(options, callback){ var jsonData = eval('Database.' + options.from), result = [], index = 0; options.where = options.where || "true"; for(var i in jsonData){ with(jsonData[i]){ if(eval(options.where)){ if(callback){ result[index++] = callback(jsonData[i]); }else{ result[index++] = jsonData[i]; } } } } return result; }, orderBy : function(result,options){ if(options.orderby.length == 0){ return result; } result.sort(function(a,b){ switch(options.order.toLowerCase()){ case "desc": return (eval('a.'+ options.orderby[0] +' < b.'+ options.orderby[0]))? 1:-1; case "asc": return (eval('a.'+ options.orderby[0] +' > b.'+ options.orderby[0]))? 1:-1; case "descnum": return (eval('a.'+ options.orderby[0] +' - b.'+ options.orderby[0])); case "ascnum": return (eval('b.'+ options.orderby[0] +' - a.'+ options.orderby[0])); } }); return result; }, limit : function(result,options){ switch(options.limit.length){ case 0: return result; case 1: return result.splice(0,options.limit[0]); case 2: return result.splice(options.limit[0],options.limit[1]); } }, extent : function(options){ switch(options.limit.length){ case 0: return {start:0, stop:9e+99}; case 1: return {start:0, stop:options.limit[0]}; case 2: return {start:options.limit[0], stop:options.limit[1]}; } } } window.jsonDB = jsonDB; //追加扩展功能 jsonDB.fn = jsonDB.prototype =extend(jsonDB.fn,DBExpand); //合并对象方法 function extend(){ var paramsLen = arguments.length; if(paramsLen<1){ return false; } var target = arguments[0]; for(var i=1;i<paramsLen;++i){ for(var j in arguments[i]){ target[j] = arguments[i][j]; } } return target; } })(window);
标签：function,case,return,json,limit,jsonDB,数据格式,options From： https://www.cnblogs.com/firespeed/p/18447759