The Web SQL Database API is not part of the HTML5 specification, but it is an independent specification that introduces a set of APIs for using SQL to operate client databases.
Core method
openDatabase-create a database object using an existing database or a new database
transaction-can control a thing, and based on In this case, execute commit or rollback
executeSql-Execute the actual SQL statement
Open the database
//用openDatabase()方法打開已存在的數(shù)據(jù)庫，如果數(shù)據(jù)庫不存在，則會(huì)創(chuàng)建一個(gè)新的數(shù)據(jù)庫var?db?=?openDatabase('mydb',?'1.0',?'Test?DB',?2?*?1024?*?1024);openDatabase( ) Description of the five parameters corresponding to the method:
Database name
Version number
Description Text
Database size (bytes)
Create callback (optional)
Five parameters, the creation callback will be called after the database is created.
Create table
var?db?=?openDatabase('mydb',?'1.0',?'Test?DB',?2?*?1024?*?1024);
db.transaction(function?(tx)?{??
???tx.executeSql('CREATE?TABLE?IF?NOT?EXISTS?LOGS?(id?unique,?log)');
});Insert data
var?db?=?openDatabase('mydb',?'1.0',?'Test?DB',?2?*?1024?*?1024);
db.transaction(function?(tx)?{
???tx.executeSql('CREATE?TABLE?IF?NOT?EXISTS?LOGS?(id?unique,?log)');
???tx.executeSql('INSERT?INTO?LOGS?(id,?log)?VALUES?(1,?"博客園")');
???tx.executeSql('INSERT?INTO?LOGS?(id,?log)?VALUES?(2,?"www.cnblogs.com")');
});Also Inserting data using dynamic values
?db?=?openDatabase(,?,?,??*??*
Reading data
var?db?=?openDatabase('mydb',?'1.0',?'Test?DB',?2?*?1024?*?1024);
?
db.transaction(function?(tx)?{
???tx.executeSql('CREATE?TABLE?IF?NOT?EXISTS?LOGS?(id?unique,?log)');
???tx.executeSql('INSERT?INTO?LOGS?(id,?log)?VALUES?(1,?"博客園")');
???tx.executeSql('INSERT?INTO?LOGS?(id,?log)?VALUES?(2,?"www.cnblogs.com")');
});
?
db.transaction(function?(tx)?{
???tx.executeSql('SELECT?*?FROM?LOGS',?[],?function?(tx,?results)?{??????var?len?=?results.rows.length;
??????msg?=?"<p>查詢記錄條數(shù):?"?+?len?+?"</p>";
??????document.querySelector('#status').innerHTML?+=??msg;????
??????for?(i?=?0;?i?<?len;?i++){
??????????msg?=?"<p><b>"?+?results.rows[i].log?+?"</b></p>";
??????}
????
???},?null);
});Deleting records
db.transaction(function?(tx)?{
????tx.executeSql('DELETE?FROM?LOGS??WHERE?id=1');
});Deleting data can also be dynamic
db.transaction(function(tx)?{
????tx.executeSql('DELETE?FROM?LOGS?WHERE?id=?',?[id]);
});Update records
tx.executeSql("UPDATE?CC?SET?logname='www.baidu.com'?WHERE?id=2");Updated data can also be dynamic
tx.executeSql("UPDATE?CC?SET?logname='www.baidu.com'?WHERE?id=?",?[id]);Note: Delete and modify cannot be placed in the same executeSql as the table creation statement. It is best to write them separately
The following is the built database
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