Android Growth Diary-sqlite[2 of data storage]

Part One:

First look at this piece of code

1Sqlitedatabase db=openorcreatedatabase ("Sqldemo.db", Mode_private,NULL);2         //Create a table3String create_sql= "CREATE table if not exists SQLTB (_id integer primary key autoincrement,name text not null,sex text not Null,age integer NOT NULL) ";4 Db.execsql (create_sql);5Db.execsql ("INSERT into SQLTB (name,sex,age) VALUES (' Zhang San ', ' Male ', ' 19 ')");6Db.execsql ("INSERT into SQLTB (name,sex,age) VALUES (' John Doe ', ' Male ', ' 20 ')");7         8Cursor c=db.rawquery ("SELECT * from SQLTB",NULL);9          if(c!=NULL)Ten          { One              while(C.movetonext ()) A             { -LOG.I ("info", "_id" +c.getint (C.getcolumnindex ("_id"))); -LOG.I ("info", "name" +c.getstring (C.getcolumnindex ("name"))); theLOG.I ("info", "Sex" +c.getstring (C.getcolumnindex ("Sex")))); -LOG.I ("Info", "Age" +c.getint (The C.getcolumnindex ("Age"))); -LOG.I ("info", "-------------------------------------------------"); -             } + c.close (); -          } + db.close (); A}

Ps:

①:openorcreatedatabase (name, mode, factory): CREATE DATABASE Database with a return value of sqlitedatabase

Name: Database names Mode: Database type factory: In order to be able to customize the cursor creation

②:execsql () This method is the statement that executes the database

③:rawquery () This method is used to query the database for information, and the return value is a cursor object

④: It needs to be closed after traversing with MoveToNext () , and it needs to be closed after the database is used to save memory.

Cons: This approach requires some knowledge of the database.

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Part:

1Sqlitedatabase db=openorcreatedatabase ("Stu.db", Mode_private,NULL);2String create= "CREATE table if not exists STUTB (_id integer primary key autoincrement,name text not null,age integer not n Ull,sex text NOT NULL) ";3Db.execsql (create);//Create a table4         /*5 * Inserting data into tables in a database6          */7Contentvalues values=Newcontentvalues ();8Values.put ("name", "Zhang San");//Key-value pair form key: Database column Name value: The contents of the corresponding column9Values.put ("Age", 18);TenValues.put ("Sex", "male"); OneDb.insert ("Stutb",NULL, values);//returns a value of type Long that is the ID of the row AValues.clear ();//clearing data for key-value pairs -Values.put ("name", "John Doe"); -Values.put ("Age", 19); theValues.put ("Sex", "female"); -Db.insert ("Stutb",NULL, values); - values.clear (); -Values.put ("name", "Harry"); +Values.put ("Age", 21); -Values.put ("Sex", "male"); +Db.insert ("Stutb",NULL, values); A values.clear (); at         /* - * Update data in the database -          */ -Values.put ("Sex", "female"); -         //db.update (table, values, Whereclause, Whereargs) -Db.update ("Stutb", Values, "_ID>?",Newstring[]{"2"});//to change all id>2 sex into a woman. in         /* - * Delete data in the database to          */ +         //db.delete (table, Whereclause, Whereargs) -Db.delete ("Stutb", "name like?",Newstring[]{"% three"});//Delete the data with three in the name the         /* * * Querying data in the database $          */Panax Notoginseng         //db.query (table, columns, selection, Selectionargs, GroupBy, having, by-and-by) -Cursor c=db.query ("Stutb",NULL, "_ID>?",Newstring[]{"0"},NULL,NULL, "name");//sort the id>0 data by name the         if(c!=NULL) +         { AString[] Columns=c.getcolumnnames (); the              while(C.movetonext ()) +             { -                 //get a row of data $                  for(String columnsname:columns) $                 { -LOG.I ("Info", C.getstring (C.getcolumnindex (Columnsname))); -                 } the             } - c.close ();Wuyi         } the db.close (); -}

Ps:

① Insert: Db.insert (table, Nullcolumnhack, values) //Parameters correspond to: Table name, default value, values value

The values are stored in the contentvalues type of data, so the object should be created: contentvalues values = new Contentvalues ();

Values.put ("Column name", "content");

② Update:db.update (table, values, Whereclause, Whereargs) //parameters corresponding to: Table name, updated content, condition, condition value (in array type new string[]{"content"})

③ Delete:db.delete (table, Whereclause, Whereargs) //parameters corresponding to: Table name condition, condition value

④ query:db.query (table, columns, selection, Selectionargs, groupBy, having, order by) //Parameters correspond to: Table name, number of columns queried (null is all), condition, condition value (in array type new string[]{"content"}), group,< default to null>, rule sort------>> return value to cursor type data

⑤ Note: The database information should be closed in time for the end of use

Android Growth Diary-sqlite[2 of data storage]