package com.asc.db; import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper; /**
* 数据库公共类，提供基本数据库操作*/
public class DBManager {
// 默认数据库
private static final String DB_NAME = "asc.db"; // 数据库版本
private static final int DB_VERSION = 1; // 执行open()打开数据库时，保存返回的数据库对象
private SQLiteDatabase mSQLiteDatabase = null; // 由SQLiteOpenHelper继承过来
private DatabaseHelper mDatabaseHelper = null; // 本地Context对象
private Context mContext = null; private static DBManager dbConn= null; // 查询游标对象
private Cursor cursor; /**
* SQLiteOpenHelper内部类
*/
private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) {
// 当调用getWritableDatabase()或 getReadableDatabase()方法时,创建一个数据库
super(context, DB_NAME, null, DB_VERSION);
} @Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE ad_record(id PRIMARY KEY NOT NULL, adUrl TEXT, apMac TEXT, createDate DATETIME);");
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS ad_record");
onCreate(db);
}
} /**
* 构造函数
*
* @param mContext
*/
private DBManager(Context mContext) {
super();
this.mContext = mContext;
} public static DBManager getInstance(Context mContext){
if (null == dbConn) {
dbConn = new DBManager(mContext);
}
return dbConn;
} /**
* 打开数据库
*/
public void open() {
mDatabaseHelper = new DatabaseHelper(mContext);
mSQLiteDatabase = mDatabaseHelper.getWritableDatabase();
} /**
* 关闭数据库
*/
public void close() {
if (null != mDatabaseHelper) {
mDatabaseHelper.close();
}
if (null != cursor) {
cursor.close();
}
} /**
* 插入数据
* @param tableName 表名
* @param nullColumn null
* @param contentValues 名值对
* @return 新插入数据的ID，错误返回-1
* @throws Exception
*/
public long insert(String tableName, String nullColumn,
ContentValues contentValues) throws Exception {
try {
return mSQLiteDatabase.insert(tableName, nullColumn, contentValues);
} catch (Exception e) {
throw e;
}
} /**
* 通过主键ID删除数据
* @param tableName 表名
* @param key 主键名
* @param id 主键值
* @return 受影响的记录数
* @throws Exception
*/
public long delete(String tableName, String key, int id) throws Exception {
try {
return mSQLiteDatabase.delete(tableName, key + " = " + id, null);
} catch (Exception e) {
throw e;
}
} /**
* 查找表的所有数据
* @param tableName 表名
* @param columns 如果返回所有列，则填null
* @return
* @throws Exception
*/
public Cursor findAll(String tableName, String [] columns) throws Exception{
try {
cursor = mSQLiteDatabase.query(tableName, columns, null, null, null, null, null);
cursor.moveToFirst();
return cursor;
} catch (Exception e) {
throw e;
}
} /**
* 根据主键查找数据
* @param tableName 表名
* @param key 主键名
* @param id 主键值
* @param columns 如果返回所有列，则填null
* @return Cursor游标
* @throws Exception
*/
public Cursor findById(String tableName, String key, int id, String [] columns) throws Exception {
try {
return mSQLiteDatabase.query(tableName, columns, key + " = " + id, null, null, null, null);
} catch (Exception e) {
throw e;
}
} /**
* 根据条件查询数据
* @param tableName 表名
* @param names 查询条件
* @param values 查询条件值
* @param columns 如果返回所有列，则填null
* @param orderColumn 排序的列
* @param limit 限制返回数
* @return Cursor游标
* @throws Exception
*/
public Cursor find(String tableName, String [] names, String [] values, String [] columns, String orderColumn, String limit) throws Exception{
try {
StringBuffer selection = new StringBuffer();
for (int i = 0; i < names.length; i++) {
selection.append(names[i]);
selection.append(" = ?");
if (i != names.length - 1) {
selection.append(",");
}
}
cursor = mSQLiteDatabase.query(true, tableName, columns, selection.toString(), values, null, null, orderColumn, limit);
cursor.moveToFirst();
return cursor;
} catch (Exception e) {
throw e;
}
} /**
*
* @param tableName 表名
* @param names 查询条件
* @param values 查询条件值
* @param args 更新列-值对
* @return true或false
* @throws Exception
*/
public boolean udpate(String tableName, String [] names, String [] values, ContentValues args) throws Exception{
try {
StringBuffer selection = new StringBuffer();
for (int i = 0; i < names.length; i++) {
selection.append(names[i]);
selection.append(" = ?");
if (i != names.length - 1) {
selection.append(",");
}
}
return mSQLiteDatabase.update(tableName, args, selection.toString(), values) > 0;
} catch (Exception e) {
throw e;
}
} /**
* 执行sql语句，包括创建表、删除、插入
*
* @param sql
*/
public void executeSql(String sql) {
mSQLiteDatabase.execSQL(sql);
} }