Initial use of Sqliteopenhelper

Inserting data

insert(table, nullColumnHack, values)

Table: Tables Name
Nullcolumnhack: Default value for empty columns
Values: A map that encapsulates column names and columns, representing a single piece of data

Delete data

db.delete(table, whereClause, whereArgs)

Table: Tables Name
Whereclause: Delete condition, can contain wildcard character "? ”
Whereargs: Delete a conditional parameter array to populate wildcard characters

Querying data

db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy)

Table: Tables Name
Columns: Column an array group
Selection: A conditional where clause, which can contain wildcards "? ”
GroupBy: Grouping columns
Having: grouping conditions
ORDER BY: Row sequence

modifying data

db.update(table, values, whereClause, whereArgs)

Table: Name of values: Updated record information
Whereclause: Updated condition that can contain wildcard characters "? ”
Whereargs: An updated array of conditional values used to populate wildcard characters

Refer to the code for specific actions:

 Public  class myhelper extends sqliteopenhelper {     Public StaticString db_name ="Note.db"; Public StaticString Tab_name ="Notes"; Public StaticString ID ="_id"; Public StaticString CONTENT ="Content"; Public StaticString DATE ="Date";PrivateSqlitedatabase DB; Public Myhelper(Context context) {Super(Context, Db_name,NULL,1); }/** * Called when creating a database * /    @Override     Public void onCreate(Sqlitedatabase db) { This. db = db; String sql =The CREATE TABLE notes (+ ID +"Integer primary key AutoIncrement,"+ CONTENT +"text,"+ DATE +"text)";//Build TableDb.execsql (SQL);//Insert some initial dataContentvalues values01 =NewContentvalues (); Values01.put (CONTENT,"I am the initial data one");        Values01.put (DATE, GETDATE ()); Contentvalues VALUES02 =NewContentvalues (); Values02.put (CONTENT,"I am the initial data two");        Values02.put (DATE, GETDATE ()); Db.insert (Tab_name,NULL, values01); Db.insert (Tab_name,NULL, VALUES02); }/** * Get current time * @return  * *     PublicStringgetdate() {Date dt =NewDate (); DateFormat DF =NewSimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"); String nowtime = df.format (DT);returnNowtime; }/** * Insert data * @param Values * *     Public void Insert(Contentvalues values)        {db = Getwritabledatabase (); Db.insert (Tab_name,NULL, values);    Db.close (); }/** * Delete data * @param Date * *     Public void Delete(String date)        {db = Getwritabledatabase (); Db.delete (Tab_name, DATE +"= ? ",NewString[] {date});    Db.close (); }/** * Query data * @return  * *     PublicCursorQuery() {db = Getwritabledatabase (); cursor cursor = db.query (Tab_name,NULL,NULL,NULL,NULL,NULL,NULL);returnCursor }/** * Update data * @param values * @param Date */     Public void Updata(Contentvalues values, String date)        {db = Getwritabledatabase (); Db.update (Tab_name, values, DATE +"= ? ",NewString[] {date}); }/** * Call */When updating several libraries    @Override     Public void Onupgrade(Sqlitedatabase DB,intOldversion,intNewVersion) {//TODO auto-generated method stub}}

Initial use of Sqliteopenhelper