Android使用SQLite数据库(1)

Android中使用SQLite数据库要通过SQLiteOpenHelper类。

首先，定义相关变量：

// 数据库变量DatabaseHelper mDBH;SQLiteDatabase db;public static String strSql;

再定义SQLiteOpenHelper类：

public static class DatabaseHelper extends SQLiteOpenHelper{public static final String DATABASE_NAME = "Call_db.db";public static final int DATABASE_VERSION = 1;public static final String TABLE_NAME = "Call";public static final String TABLE_NAME_2 = "Days";public static final String NAME = "Name";public static final String NUMBER = "Number";public static final String DATE = "Date";public static final String DATES = "Dates";public static final String YEAR = "Year";public static final String MONTH = "Month";public static final String DAY = "Day";public static final String HOUR = "Hour";public static final String MINUTE = "Minute";public static final String DOW = "Dow";public static final String TYPE = "Type";public static final String INC = "InC";public static final String OUTC = "OutC";public static final String TOTAL = "Total";DatabaseHelper(Context context){super(context, DATABASE_NAME, null, DATABASE_VERSION);}// 没有数据库时，建立数据库@Overridepublic void onCreate(SQLiteDatabase db) {strSql = "CREATE TABLE " + TABLE_NAME + " (" + NAME+ " text not null, " + NUMBER + " text not null, " + DATE + " text not null, " + DATES+ " text not null, "+ YEAR + " text not null, " + MONTH + " text not null, " + DAY + " text not null, " + HOUR + " text not null, " + MINUTE + " text not null, " + DOW  + " text not null, " + TYPE + " text not null" + ");";db.execSQL(strSql);strSql = "CREATE TABLE " + TABLE_NAME_2 + " (" + DATES+ " text not null, " + YEAR + " text not null, " + MONTH + " text not null, " + DAY+ " text not null, "+ DOW + " text not null, " + INC + " text not null, " + OUTC + " text not null, " + TOTAL + " text not null);";db.execSQL(strSql);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}}

当数据库不存在时（如第一次运行时），调用onCreate(SQLiteDatabase db)建立数据库，建立的方法是定义SQL语句，再执行该语句。

更多相关文章

随机推荐