在之前，我写了一个websql的封装类库，代码如下：
(function(win) {
function smpWebSql(options){
options = options || {};
this.database = null;
this.DateBaseName = options.DateBaseName || ‘SmpDB‘;
this.Version = options.Version || ‘1.0‘;
this.Description = options.Description || ‘SmpDB‘;
this.DataBaseSize = options.DataBaseSize || 2 * 1024 * 1024;
this.init();
}
smpWebSql.prototype = {
init: function() {
this.database = openDatabase(this.DateBaseName, this.Version, this.Description, this.DataBaseSize); //初始化数据库
},
addBlob: function (tableName, arr,index,isFirst,callback) {//批量添加字段
/*
注 ： 数据里面的第一个key存储类型为BLOB
@param tableName 表名
@param arr 更新的数据 [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
@param index BLOG字段所在的索引位置
@param isFirst 是否是第一次创建表
@param callback 回调
*/
if (arr == null) {
return this;
}
callback = this.isFunction(callback) ? callback : new Function();
var _me = this,
_db = this.database,
keyC = [],
keyI = [],
_key = ‘‘;
arr = arr || [];
if (arr && arr.constructor == Array) {
for (var i in arr[0]) {
keyC.push(i);
keyI.push(i);
}
_key = keyI.join(",");
index = index == undefined ? 0 : index;
keyC[index] = keyC[index] + ‘ BLOB‘;
_db.transaction(function (tx, result) {
//var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
//console.log(‘csql:‘ + csql);
if (isFirst == true) {
tx.executeSql(‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘);
}
//var sql = "";
for (var s = 0, _len = arr.length; s < _len ; s++) {
var _value = _me.split(arr[s]);
//sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
//console.log("sql:" + sql);
tx.executeSql(‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘,[],function (tx, result) {
callback(result.rowsAffected);
//console.log(‘添加成功‘+result.rowsAffected);
},function (tx, error) {
console.error(‘添加失败‘);
callback(false);
});
}
_key = keyI = keyC = null;
callback();
});
}
return this;
},
add: function (tableName, arr, callback, noKey) {//批量添加字段
/*
注 ： 数据里面的第一个key 为主键
@param tableName 表名
@param arr 更新的数据 [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
@param callback 回调
@param noKey 第一个字段是否是主键（默认是）
*/
if(arr==null){
return this;
}
callback = this.isFunction(callback) ? callback : new Function();
var _me = this,
_db = this.database,
keyC = [],
keyI = [],
_key = ‘‘;
arr = arr || [];
if (arr && arr.constructor == Array) {
for(var i in arr[0]){
keyC.push(i);
keyI.push(i);
}
if (noKey==undefined) {
keyC[0] = keyC[0] + ‘ unique‘;
}
_key = keyI.join(",");
_db.transaction(function (tx) {
///var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
// console.log(‘csql:‘ + csql);
tx.executeSql(‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘);
//var sql = "";
for(var s = 0 , _len = arr.length; s < _len ; s++){
var _value = _me.split(arr[s]);
//sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
//console.log("sql:" + sql);
tx.executeSql(‘INSERT INTO ‘+tableName+‘ (‘+_key+‘) VALUES (‘+_value+‘)‘,[],function (tx, result) {
callback(result.rowsAffected);
//console.log(‘添加成功‘+result.rowsAffected);
},function (tx, error) {
console.error(‘添加失败‘);
callback(false);
});
}
_key = keyI = keyC = null;
callback();
});
}
return this;
},
update : function(tableName,key,value,obj,callback){//更新指定数据
/*
@param tableName 表名
@param key 查询的键
@param value 对应键的值
@param obj 更新的数据 {key1：value1 , key2 : value2 ...}
@param callback 回调 传递参数为真则查询成功 反之更新失败
*/
callback = this.isFunction(callback) ? callback : new Function();
var _db = this.database,
_value = this.splitU(obj);
_db.transaction(function (tx) {
//console.log(‘sql:‘ + ‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + key + ‘="‘ + value + ‘"‘)
tx.executeSql(‘UPDATE ‘+tableName+‘ set ‘+_value+‘ where ‘+key+‘="‘+value+‘"‘,[],function (tx, result) {
callback(result.rowsAffected);
},function (tx, error) {
console.error(‘更新失败‘);
callback(false);
});
});
return this;
},
updateWhere: function (tableName, where, obj, callback) {//更新指定数据
/*
@param tableName 表名
@param 查询条件
@param obj 更新的数据 {key1：value1 , key2 : value2 ...}
@param callback 回调 传递参数为真则查询成功 反之更新失败
*/
callback = this.isFunction(callback) ? callback : new Function();
var _db = this.database,
_value = this.splitU(obj);
_db.transaction(function (tx) {
console.log(‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + where + ‘"‘)
tx.executeSql(‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + where + ‘"‘, [], function (tx, result) {
callback(result.rowsAffected);
}, function (tx, error) {
console.error(‘更新失败‘);
callback(false);
});
});
return this;
},
read : function(tableName,condition,callback){ //读取表数据
/*
@param tableName 表名
@param condition 查询条件 ‘where name="汪文君"‘
@param callback 回调 传递参数为真则查询成功 反之查询失败
*/
var _condition = this.isString(condition) ? condition : ‘‘;
var _callback = this.isFunction(condition) ? condition : this.isFunction(callback) ? callback : new Function;
var _db = this.database,
_me = this,
_re = [];
_db.transaction(function (tx) {
tx.executeSql(‘SELECT * FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘, [], function (tx, results) {
if(results && results.rows){
_re =_me.toArray(results.rows);
_callback(_re);
}else{
_callback([]);
}
},function(tx,error){
_callback([]);
console.error(‘查询失败‘);
});
});
return this;
},
remove:function(tableName,condition,callback){//删除数据
/*
@param tableName 表名
@param condition 查询条件 ‘where name="汪文君"‘
@param callback 回调 传递参数为真则删除成功 反之删除失败
*/
var _me = this;
var _condition = this.isString(condition) ? condition : ‘‘;
var _callback = this.isFunction(condition) ? condition : this.isFunction(callback) ? callback : new Function;
_me.database.transaction(function (tx) {
tx.executeSql(‘DELETE FROM ‘+tableName+ ‘ ‘+ _condition+‘ ‘,[],function (tx, result) {
_callback(result.rowsAffected);
},function (tx, error) {
_callback(false);
console.error(‘删除失败‘);
});
});
},
counts: function (tableName, condition, callback) { //读取表数据
/*
@param tableName 表名
@param condition 查询条件 ‘where name="汪文君"‘
@param callback 回调 传递参数为真则查询成功 反之查询失败
*/
var _condition = this.isString(condition) ? condition : ‘‘;
var _callback = this.isFunction(condition) ? condition : this.isFunction(callback) ? callback : new Function;
var _db = this.database,
_me = this,
_re = [];
if (mui.os.ios) { //ios下面特有的
_db.transaction(function (tx) {
tx.executeSql(‘SELECT NO FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘, [], function (tx, results) {// count (*) as num
if (results && results.rows) {
_re = _me.toArray(results.rows);
_callback(_re.length);
} else {
_callback(0);
}
}, function (tx, error) {
_callback(0);
console.error(‘查询失败‘);
});
});
} else {
_db.transaction(function (tx) {
tx.executeSql(‘SELECT count (*) as num FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘, [], function (tx, results) {// count (*) as num
if (results && results.rows) {
if (results.rows[0]) {
_callback(results.rows[0].num);
} else {
_callback(0);
}
} else {
_callback(0);
}
}, function (tx, error) {
_callback(0);
console.error(‘查询失败‘);
});
});
}
return this;
},
delTable:function(tableName,callback){ //删除数据表
callback = this.isFunction(callback) ? callback : new Function();
this.database.transaction(function(tx){
tx.executeSql(‘DROP TABLE IF EXISTS ‘+tableName,[],function(tx,res){
callback();
},function(tx,err){
console.error(err);
});
});
return this;
},
splitU: function(obj){//更新字符处理
var _arr = [];
for(var t in obj){
_arr.push(t+‘="‘+obj[t]+‘"‘);
}
return _arr.join(‘,‘);
},
split : function(obj){//添加字符处理
var _arr = [];
for(var m in obj){
_arr.push("‘"+obj[m]+"‘");
}
return _arr.join(‘,‘);
},
isFunction : function(callback){
return typeof callback != ‘undefined‘ && callback.constructor == Function ? true : false
},
isString : function(string){
return typeof string == ‘string‘ ? true : false
},
toArray : function(obj){
var _arr = [],
_len = obj.length;
if(_len > 0){
for (var i = 0; i < _len; i++) {
_arr.push(obj.item(i));
};
}
return _arr;
}
}
win.smpWebSql = smpWebSql;
}(window))
上述代码存在的问题非常明显，由于websql操作都是异步操作，当我们为了获取到websql操作的结果之后再进行后续操作时，往往是通过回调函数来实现的，当回调一多的时候，回调地狱就出现了，为了解决回调地狱问题，我将通过Promise来改写，后续调用时，可以直接通过await和async来调用，或者直接通过Promise链式调用也是可以的。
现在我将通过ES6的语法重写之前的封装类，为了应用ES6中js面向对象的思想，我这里用到了class，最终代码如下：
import utils from ‘@/utils/utils.js‘;
class SmpWebSql {
constructor(options) {
options = options || {};
this.database = null;
this.DateBaseName = options.DateBaseName || ‘RedDB‘;
this.Version = options.Version || ‘1.0‘;
this.Description = options.Description || ‘智维离线工单数据库‘;
this.DataBaseSize = options.DataBaseSize || 2 * 1024 * 1024;
this.init();
}
/**
* 初始化数据库
*/
init() {
this.database = openDatabase(
this.DateBaseName,
this.Version,
this.Description,
this.DataBaseSize
);
}
/**
* 批量添加字段
* @param {*} tableName 表名
* @param {*} arr 更新的数据 [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
* @param {*} index BLOG字段所在的索引位置
* @param {*} isFirst 是否是第一次创建表
*/
addBlob(tableName, arr, index, isFirst) {
var _db = this.database;
var _me = this;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
if (arr == null) {
return this;
}
var keyC = [];
var keyI = [];
var _key = ‘‘;
arr = arr || [];
if (arr && arr.constructor == Array) {
for (var i in arr[0]) {
keyC.push(i);
keyI.push(i);
}
_key = keyI.join(‘,‘);
index = index == undefined ? 0 : index;
keyC[index] = keyC[index] + ‘ BLOB‘;
// eslint-disable-next-line promise/param-names
_db.transaction(function(tx, result) {
// var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
// console.log(‘csql:‘ + csql);
if (isFirst == true) {
tx.executeSql(
‘CREATE TABLE IF NOT EXISTS ‘ +
tableName +
‘ (‘ +
keyC.join(‘,‘) +
‘)‘
);
}
// var sql = "";
for (var s = 0, _len = arr.length; s < _len; s++) {
var _value = _me.split(arr[s]);
// sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
// console.log("sql:" + sql);
tx.executeSql(
‘INSERT INTO ‘ +
tableName +
‘ (‘ +
_key +
‘) VALUES (‘ +
_value +
‘)‘,
[],
function(tx, result) {
resovle(result.rowsAffected);
// console.log(‘添加成功‘+result.rowsAffected);
},
function(tx) {
console.error(‘添加失败‘);
// eslint-disable-next-line prefer-promise-reject-errors
reject(false);
}
);
}
_key = keyI = keyC = null;
resovle();
});
}
});
}
/**
* 批量添加字段 注 ： 数据里面的第一个key 为主键
* @param {*} tableName 表名
* @param {*} arr arr 更新的数据 [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
* @param {*} noKey noKey 第一个字段是否是主键（默认是）
*/
add(tableName, arr, noKey) {
var _me = this;
var _db = this.database;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
if (arr == null) {
return this;
}
var keyC = [];
var keyI = [];
var _key = ‘‘;
arr = arr || [];
if (arr && arr.constructor == Array) {
for (var i in arr[0]) {
keyC.push(i);
keyI.push(i);
}
if (noKey == undefined) {
keyC[0] = keyC[0] + ‘ unique‘;
}
_key = keyI.join(‘,‘);
_db.transaction(function(tx) {
// /var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
// console.log(‘csql:‘ + csql);
tx.executeSql(
‘CREATE TABLE IF NOT EXISTS ‘ +
tableName +
‘ (‘ +
keyC.join(‘,‘) +
‘)‘
);
// var sql = "";
for (var s = 0, _len = arr.length; s < _len; s++) {
var _value = _me.split(arr[s]);
// sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
// console.log("sql:" + sql);
tx.executeSql(
‘INSERT INTO ‘ +
tableName +
‘ (‘ +
_key +
‘) VALUES (‘ +
_value +
‘)‘,
[],
function(tx, result) {
resovle(result.rowsAffected);
// console.log(‘添加成功‘+result.rowsAffected);
},
function(tx, error) {
console.error(‘添加失败‘);
// eslint-disable-next-line prefer-promise-reject-errors
reject(false);
}
);
}
_key = keyI = keyC = null;
// resovle();
});
}
});
}
/**
* 更新指定数据
* @param {*} tableName 表名
* @param {*} key 查询的键
* @param {*} value 对应键的值
* @param {*} obj obj 更新的数据 {key1：value1 , key2 : value2 ...}
*/
update(tableName, key, value, obj) {
var _db = this.database;
var _value = this.splitU(obj);
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
_db.transaction(function(tx) {
// console.log(‘sql:‘ + ‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + key + ‘="‘ + value + ‘"‘)
tx.executeSql(
‘UPDATE ‘ +
tableName +
‘ set ‘ +
_value +
‘ where ‘ +
key +
‘="‘ +
value +
‘"‘,
[],
function(tx, result) {
resovle(result.rowsAffected);
},
function(tx, error) {
console.error(‘更新失败‘);
// eslint-disable-next-line prefer-promise-reject-errors
reject(false);
}
);
});
});
}
/**
* 更新指定数据
* @param {*} tableName 表名
* @param {*} where 查询条件
* @param {*} obj obj 更新的数据 {key1：value1 , key2 : value2 ...}
*/
updateWhere(tableName, where, obj) {
var _db = this.database;
var _value = this.splitU(obj);
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
_db.transaction(function(tx) {
console.log(
‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + where + ‘"‘
);
tx.executeSql(
‘UPDATE ‘ + tableName + ‘ set ‘ + _value + ‘ where ‘ + where + ‘"‘,
[],
function(tx, result) {
resovle(result.rowsAffected);
},
function(tx, error) {
console.error(‘更新失败‘);
// eslint-disable-next-line prefer-promise-reject-errors
reject(false);
}
);
});
});
}
/**
* 读取表数据
* @param {*} tableName 表名
* @param {*} condition 查询条件 ‘where name="jiekzou"‘
*/
read(tableName, condition) {
var _db = this.database;
var _me = this;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
var _condition = this.isString(condition) ? condition : ‘‘;
var _re = [];
_db.transaction(function(tx) {
tx.executeSql(
‘SELECT * FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘,
[],
function(tx, results) {
if (results && results.rows) {
_re = _me.toArray(results.rows);
resovle(_re);
} else {
resovle([]);
}
},
function(tx, error) {
// eslint-disable-next-line prefer-promise-reject-errors
reject([]);
console.error(‘查询失败‘);
}
);
});
});
}
/**
* 删除数据
* @param {*} tableName 表名
* @param {*} condition 查询条件 ‘where name="jiekzou"‘
*/
remove(tableName, condition) {
var _me = this;
var _condition = this.isString(condition) ? condition : ‘‘;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
_me.database.transaction(function(tx) {
tx.executeSql(
‘DELETE FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘,
[],
function(tx, result) {
resovle(result.rowsAffected);
},
function(tx, error) {
// eslint-disable-next-line prefer-promise-reject-errors
reject(false);
console.error(‘删除失败‘);
}
);
});
});
}
/**
* 根据查询条件读取表记录数
* @param {*} tableName 表名
* @param {*} condition 查询条件 ‘where name="jiekzou"‘
*/
counts(tableName, condition) {
if (utils.browserVersions.android) {
return this.androidCounts(tableName, condition);
} else {
return this.iosCounts(tableName, condition);
}
}
// ios下面特有的
/**
* 读取表数据(ios下面特有的)
* @param {*} tableName 表名
* @param {*} condition 查询条件 ‘where name="jiekzou"‘
*/
iosCounts(tableName, condition) {
var _condition = this.isString(condition) ? condition : ‘‘;
var _db = this.database;
var _me = this;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
var _re = [];
_db.transaction(function(tx) {
tx.executeSql(
‘SELECT NO FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘,
[],
function(tx, results) {
// count (*) as num
if (results && results.rows) {
_re = _me.toArray(results.rows);
resovle(_re.length);
} else {
resovle(0);
}
},
function(tx, error) {
// eslint-disable-next-line prefer-promise-reject-errors
reject(0);
console.error(‘查询失败‘);
}
);
});
});
}
/**
* 读取表数据（Android）
* @param {*} tableName 表名
* @param {*} condition 查询条件 ‘where name="jiekzou"‘
*/
androidCounts(tableName, condition) {
var _condition = this.isString(condition) ? condition : ‘‘;
var _db = this.database;
var _me = this;
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
var _re = [];
_db.transaction(function(tx) {
tx.executeSql(
‘SELECT count (*) as num FROM ‘ + tableName + ‘ ‘ + _condition + ‘ ‘,
[],
function(tx, results) {
// count (*) as num
if (results && results.rows) {
if (results.rows[0]) {
resovle(results.rows[0].num);
} else {
resovle(0);
}
} else {
resovle(0);
}
},
function(tx, error) {
// eslint-disable-next-line prefer-promise-reject-errors
reject(0);
console.error(‘查询失败‘);
}
);
});
});
}
/**
* 删除数据表
* @param {*} tableName 表名
*/
delTable(tableName) {
// eslint-disable-next-line promise/param-names
return new Promise(function(resovle, reject) {
this.database.transaction(function(tx) {
tx.executeSql(
‘DROP TABLE IF EXISTS ‘ + tableName,
[],
function(tx, res) {
resovle();
},
function(tx, err) {
console.error(err);
// eslint-disable-next-line prefer-promise-reject-errors
reject(0);
}
);
});
});
}
// 更新字符处理
splitU(obj) {
var _arr = [];
for (var t in obj) {
_arr.push(t + ‘="‘ + obj[t] + ‘"‘);
}
return _arr.join(‘,‘);
}
// 添加字符处理
split(obj) {
var _arr = [];
for (var m in obj) {
_arr.push(‘\‘‘ + obj[m] + ‘\‘‘);
}
return _arr.join(‘,‘);
}
isFunction(callback) {
return !!(
typeof callback != ‘undefined‘ && callback.constructor == Function
);
}
isString(string) {
return typeof string == ‘string‘;
}
toArray(obj) {
var _arr = [];
var _len = obj.length;
if (_len > 0) {
for (var i = 0; i < _len; i++) {
_arr.push(obj.item(i));
}
}
return _arr;
}
}
export default SmpWebSql;
原文地址：https://www.cnblogs.com/jiekzou/p/11366121.html
时间： 2024-11-02 20:14:36