操作sqlite的JavaScript类详解编程语言

/*************************************/ 
/* Helman, heldes.com      */ 
/* helman at heldes dot com    */ 
/* sqlitedb.js           */ 
/* SQLite Database Class For HTML5 */ 
/*************************************/ 
function cDB(confs) { 
var ret = { 
_db : null, 
_response : null, 
_error : null, 
check : function (tbl) { 
if (!this._db) 
return false; 
var _sql = '', 
_sqlField = '', 
_field = []; 
for (var i = 0; i < tbl.length; i++) { 
_sql = "CREATE TABLE IF NOT EXISTS " + tbl[i].table + " ("; 
_field = tbl[i].properties; 
_sqlField = ''; 
for (var j = 0; j < _field.length; j++) { 
_sqlField += ',`' + _field[j].name + '` ' + _field[j].type; 
} 
_sql += _sqlField.substr(1) + ");"; 
this.query(_sql, null, null, null); 
} 
return true; 
}, 
getResult : function () { 
return this._response; 
}, 
getError : function () { 
return this._error; 
}, 
callback_error : function (tx, _er) { 
var err = ''; 
if (typeof(tx) == 'object') { 
for (var q in tx) { 
err += q + ' = "' + tx[q] + '"; '; 
} 
} else { 
err += tx + '; '; 
} 
if (typeof(_er) == 'object') { 
for (var q in _er) { 
err += q + ' = "' + _er[q] + '"; '; 
} 
} else if (typeof(_er) == 'undefined') { 
err += _er + '; '; 
} 
console.log(err); 
//if(callback) callback(); 
return false; 
}, 
query : function (sql, callback, params, er) { 
if (!this._db) 
return false; 
var self = this; 
function _er(tx, __er) { 
__er = jQuery.extend(__er, { 
sql : sql 
}); 
if (er) 
er(tx, __er); 
else 
self.callback_error(tx, __er); 
}; 
this._db.transaction(function (tx) { 
tx.executeSql(sql, (params ? params : []), callback, _er); 
}, _er); 
}, 
update : function (tbl, sets, clauses, callback) { 
var __sql = 'UPDATE ' + tbl, 
_field = null, 
__set = '', 
__clause = '', 
__values = []; 
for (var i = 0; i < sets.length; i++) { 
0 
_field = sets[i]; 
for (var j = 0; j < _field.length; j++) { 
__set += ',`' + _field[j].name + '`=?'; 
__values.push(_field[j].value); 
} 
} 
for (var i = 0; i < clauses.length; i++) { 
__clause += ',`' + clauses[i].name + '`=?'; 
__values.push(clauses[i].value); 
} 
__sql += ((__set != '') ? ' SET ' + __set.substr(1) : '') + ((__clause != '') ? ' WHERE ' + __clause.substr(1) : '') + ';'; 
this.query(__sql, callback, __values); 
return true; 
}, 
remove : function (tbl, clauses) { 
var __sql = 'DELETE FROM ' + tbl, 
__clause = ''; 
for (var i = 0; i < clauses.length; i++) 
__clause += ',`' + clauses[i].name + '`="' + escape(clauses[i].value) + '"'; 
__sql += ' WHERE ' + ((__clause != '') ? __clause.substr(1) : 'FALSE') + ';'; 
this.query(__sql); 
return true; 
}, 
multiInsert : function (tbl, rows, callback, er) { 
if (!this._db) 
return false; 
var self = this; 
var __sql = '', 
_field = null, 
__field = '', 
__qs = [], 
__values = []; 
this._db.transaction(function (tx) { 
for (var i = 0; i < rows.length; i++) { 
__qs = []; 
__values = []; 
__field = ''; 
_field = rows[i]; 
for (var j = 0; j < _field.length; j++) { 
__field += ',`' + _field[j].name + '`'; 
__qs.push('?'); 
__values.push(_field[j].value); 
} 
tx.executeSql('INSERT INTO ' + tbl + ' (' + __field.substr(1) + ') VALUES(' + __qs.join(',') + ');', __values, function () { 
return false; 
}, (er ? er : self.callback_error)); 
} 
}, self.callback_error, function () { 
if (callback) 
callback(); 
return true; 
}); 
return true; 
}, 
insert : function (tbl, rows, callback) { 
var __sql = '', 
_field = null, 
__field = '', 
__qs = [], 
__values = [], 
__debug = ''; 
for (var i = 0; i < rows.length; i++) { 
__qs = []; 
__field = ''; 
_field = rows[i]; 
__debug += _field[0].name + ' = ' + _field[0].value + ';'; 
for (var j = 0; j < _field.length; j++) { 
__field += ',`' + _field[j].name + '`'; 
__qs.push('?'); 
__values.push(_field[j].value); 
} 
__sql += 'INSERT INTO ' + tbl + ' (' + __field.substr(1) + ') VALUES(' + __qs.join(',') + ');'; 
} 
this.query(__sql, callback, __values); 
return true; 
}, 
insertReplace : function (tbl, rows, debug) { 
var __sql = '', 
_field = null, 
__field = '', 
__qs = [], 
__values = [], 
__debug = ''; 
for (var i = 0; i < rows.length; i++) { 
__qs = []; 
__field = ''; 
_field = rows[i]; 
__debug += _field[0].name + ' = ' + _field[0].value + ';'; 
for (var j = 0; j < _field.length; j++) { 
__field += ',`' + _field[j].name + '`'; 
__qs.push('?'); 
__values.push(_field[j].value); 
} 
__sql += 'INSERT OR REPLACE INTO ' + tbl + ' (' + __field.substr(1) + ') VALUES(' + __qs.join(',') + ');'; 
} 
this.query(__sql, null, __values); 
return true; 
}, 
dropTable : function (tbl, callback) { 
var __sql = ''; 
if (tbl == null) 
return false; 
__sql = 'DROP TABLE IF EXISTS ' + tbl; 
this.query(__sql, callback); 
return true; 
} 
} 
return jQuery.extend(ret, confs); 
} 
/*=======================================*/ 
使用方法： 
/*=======================================*/ 
/*=======================================*/ 
创建数据库： 
/* Create or open database with 'websiteDB' as database name and 'website DB' as title, and database site is 5MB */ 
/* I'm not using 1024 for the size multiplying because i don't want to be near at the margin size                          */ 
var db = new cDB({ 
_db : window.openDatabase("websiteDB", "", "website DB"; , 5 * 1000 * 1000) 
}); 
/*=======================================*/ 
建表 : 
/* dbTable is database structure in this example, and contains 2 tables 'foo' and 'boo' */ 
/* and also the table structure in table properties                                                           */ 
var dbTable = [{ 
table : 'foo', 
properties : [{ 
name : 'foo_id', 
type : 'INT PRIMARY KEY ASC' 
}, { 
name : 'foo_field_1', 
type : '' 
}, { 
name : 'foo)field_2', 
type : '' 
} 
] 
}, { 
table : 'boo', 
properties : [{ 
name : 'boo_id', 
type : 'INT PRIMARY KEY ASC' 
}, { 
name : 'boo_field_1', 
type : '' 
}, { 
name : 'boo_field_2', 
type : '' 
} 
] 
} 
]; 
/* this line is checking if the database exist or not and then create the database structure.  */ 
/* table will be created if the table is not exist yet, if the table already exist, it will skip the */ 
/* table and continue with others tables                                                                                  */ 
if (!db.check(dbTable)) { 
db = false; 
alert('Failed to cennect to database.'); 
} 
/*=======================================*/ 
删除表： 
db.dropTable('foo'); 
/*=======================================*/ 
插入数据： 
var row = []; 
row.push([{ 
'name' : 'foo_id', 
'value' : 1 
}, { 
'name' : 'foo_field_1', 
'value' : 'value 1 field_1' 
}, { 
'name' : 'foo_field_2', 
'value' : 'value 1 field_2'] 
} 
]); 
db.insert('foo', row); 
插入多行记录： 
/* 
SQLite is not accepting more than 1 line statement, 
that is the reason why we not able to do more than one statement query, like insertion. 
If you want to insert more than 1 record at the time, you need to use this function. 
*/ 
var rows = []; 
rows.push([{ 
'name' : 'boo_id', 
'value' : 1 
}, { 
'name' : 'boo_field_1', 
'value' : 'value 1 field_1' 
}, { 
'name' : 'boo_field_2', 
'value' : 'value 1 field_2'] 
} 
]); 
rows.push([{ 
'name' : 'boo_id', 
'value' : 2 
}, { 
'name' : 'boo_field_1', 
'value' : 'value 2 field_1' 
}, { 
'name' : 'boo_field_2', 
'value' : 'value 2 field_2'] 
} 
]); 
db.multiInsert('boo', rows, function () { 
alert('insertion done'); 
}); 
/* 
如果想合并insert 和 multiInsert两个函数，可以按下面的方法增加一个判断来处理 
*/ 
if (rows.length >= 2) { 
db.multiInsert('boo', rows, function () { 
alert('insertion done'); 
}); 
} else { 
db.insert('boo', rows); 
} 
/*=======================================*/ 
删除数据： 
db.remove('boo', [{ 
'name' : 'boo_id', 
'value' : 1 
} 
]) 
/*=======================================*/ 
更新数据 
db.update('boo', [[{ 
'name' : 'boo_id', 
'value' : 2 
}, { 
'name' : 'boo_field_1', 
'value' : 'boo value' 
} 
]], ['name' : 'boo_id', 'value' : 2]) 
/*=======================================*/ 
查询 
var query = 'SELECT * FROM foo'; 
db.query(query, function (tx, res) { 
if (res.rows.length) { 
alert('found ' + res.rows.length + ' record(s)'); 
} else { 
alert('table foo is empty'); 
} 
});