HTML5 Web SQL

Original address: http://www.cnblogs.com/xumingxiang/archive/2012/03/25/2416418.html

Web SQL database (detail URL:http://www.w3.org/TR/2008/WD-html5-20080610/structured.html )

Web SQLdatabase: Databases API(IE and Firefox not supported)

HTML5 Database API:

OpenDatabase : Create a Database object using an existing database or creating a new database.

Transaction : Allows the user to control the transaction commit or rollback, depending on the situation.

ExecuteSQL : used to perform a real SQL query.

There are two necessary steps to writing a sqllite database using javascript scripting :

Creates an object that accesses the database.

Use transaction processing.

1. Create or open a database opendatabase

Use the opendatabase method to create an object that accesses the database.

Database OpenDatabase (in domstring name,in domstring version,in domstring displayname,in unsigned long estimatedsize,in o Ptional databasecallback Creationcallback)

OpenDatabase () method: You can open a database that already exists and create it if it does not exist.

Five parameters: Database name, version number, description, database size, and create callback.

Note: To detect whether the connection was successful.

2. Accessing and manipulating Databases transaction

Db.transction (Function (TX) {})

Transaction.executesql (Sqlquery,[],datahandler,errorhandler)

extension: After executing executesql , There is a parameter resultin the DataHandler callback function.

Result: The data set that is queried. Its data type is sqlresultset .  

The SqlResultSet is defined as:

Interface SqlResultSet {

readonly attribute long Insertid;

readonly attribute long rowsaffected;

readonly attribute sqlresultsetrowlist rows;

};

Insertid: is an insert operation that represents the first number of data inserted into a table, when inserting multiple data, returns the ordinal of the last data corresponding

Rowsaffected: Represents the number of rows affected, for example, performing an update operation and updating a data, then it is 1

rows: Returns a sqlresultsetrowlist type of data

Interface Sqlresultsetrowlist {

ReadOnly attribute unsigned long length;

[Indexgetter] Domobject item (in unsigned long index);

};

result.rows.length: Returns the number of items per line

result.rows.item (0) ["id"] or result.rows.item (0). ID; : Returns each item

HTML5 Web SQL