SQLite 是一个软件库，实现了自给自足的、无服务器的、零配置的、事务性的 SQL 数据库引擎。SQLite 是在世界上最广泛部署的 SQL 数据库引擎。SQLite 源代码不受版权限制。
Android开发中，sdk提供了SQLiteDatabase类，有响应调用数据操作的api。
1、面对象，先创建表对应的实体类
public class DbEntity {
private int id;
private int p_id;
private int c_id;
private int d_id;
private String province;
private String city;
private String district;
private String address;
private String attr;
protected DbEntity(){
}
public DbEntity(int p_id, int c_id, int d_id, String province, String city, String district, String address, String attr) {
this.p_id = p_id;
this.c_id = c_id;
this.d_id = d_id;
this.province = province;
this.city = city;
this.district = district;
this.address = address;
this.attr = attr;
}
}2、封装SQLiteDatabase工具类实现curd
public class DBUtils extends SQLiteOpenHelper {
private static final String DB_NAME = "data.db";
private static final int VERSION = 1;
private static final String TABLE_NAME = "t_table";
private SQLiteDatabase mDatabase;
public DBUtils(Context context) {
super(context, DB_NAME, null, VERSION);
}
public void setDb(SQLiteDatabase db) {
this.mDatabase = db;
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "create table if not exists "
+ TABLE_NAME +
" (id integer primary key autoincrement,p_id integer,c_id integer,d_id integer,province varchar(20),city varchar(50),district varchar(100),address varchar(200),attr varchar(200))";
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS " + TABLE_NAME;
db.execSQL(sql);
onCreate(db);
}
public void closeDb() {
if (mDatabase != null)
mDatabase.close();
}
public void insertBySql(DbEntity dbEntity) {
mDatabase.beginTransaction();
//sql中字符串字段一定要使用 ''
StringBuilder sb = new StringBuilder();
sb.append("'").append(dbEntity.getProvince()).append("'").append(",");
sb.append("'").append(dbEntity.getCity()).append("'").append(",");
sb.append("'").append(dbEntity.getDistrict()).append("'").append(",");
sb.append("'").append(dbEntity.getAddress()).append("'").append(",");
sb.append("'").append(dbEntity.getAttr()).append("'");
String sql = "insert into " + TABLE_NAME +
"(p_id,c_id,d_id,province,city,district,address,attr) values("
+ dbEntity.getP_id() + "," + dbEntity.getC_id() + "," + dbEntity.getD_id() + ","
+ sb.toString() + ")";
mDatabase.execSQL(sql);
mDatabase.setTransactionSuccessful();
}
public void insertByContentValues(DbEntity dbEntity) {
String[] columns = {"id", "p_id", "province", "c_id", "city", "d_id", "district", "address", "attr"};
ContentValues values = new ContentValues();
values.put(columns[0], dbEntity.getP_id());
values.put(columns[1], dbEntity.getProvince());
values.put(columns[2], dbEntity.getC_id());
values.put(columns[3], dbEntity.getCity());
values.put(columns[4], dbEntity.getD_id());
values.put(columns[5], dbEntity.getDistrict());
values.put(columns[6], dbEntity.getAddress());
values.put(columns[7], dbEntity.getAttr());
mDatabase.insert(TABLE_NAME, "", values);
}
public void update(DbEntity dbEntity) {
mDatabase.beginTransaction();
String sql = "update " + TABLE_NAME + " set " +
"p_id=" + "'" + dbEntity.getP_id() + "'" +
",province=" + "'" + dbEntity.getProvince() + "'" +
",c_id=" + "'" + dbEntity.getC_id() + "'" +
",city=" + "'" + dbEntity.getCity() + "'" +
",d_id=" + "'" + dbEntity.getD_id() + "'" +
",district=" + "'" + dbEntity.getDistrict() + "'" +
",attr=" + "'" + dbEntity.getAttr() + "'" +
"where id=" + dbEntity.getId();
mDatabase.execSQL(sql);
mDatabase.setTransactionSuccessful();
}
public void delete(DbEntity dbEntity) {
String sql = "delete from " + TABLE_NAME + "where _id" + dbEntity.getId();
mDatabase.execSQL(sql);
}
public List<DbEntity> findAll() {
List<DbEntity> list = new ArrayList<>();
String[] columns = {"id", "p_id", "province", "c_id", "city", "d_id", "district", "address", "attr"};
String orderBy = "id desc";
Cursor cursor = mDatabase.query(TABLE_NAME, columns, "", null, null, null, orderBy);
DbEntity dbEntity;
while (cursor.moveToNext()) {
dbEntity = new DbEntity();
dbEntity.setId(cursor.getInt(cursor.getColumnIndex(columns[0])));
dbEntity.setP_id(cursor.getInt(cursor.getColumnIndex(columns[1])));
dbEntity.setProvince(cursor.getString(cursor.getColumnIndex(columns[2])));
dbEntity.setC_id(cursor.getInt(cursor.getColumnIndex(columns[3])));
dbEntity.setCity(cursor.getString(cursor.getColumnIndex(columns[4])));
dbEntity.setD_id(cursor.getInt(cursor.getColumnIndex(columns[5])));
dbEntity.setDistrict(cursor.getString(cursor.getColumnIndex(columns[6])));
dbEntity.setAddress(cursor.getString(cursor.getColumnIndex(columns[7])));
dbEntity.setAttr(cursor.getString(cursor.getColumnIndex(columns[8])));
list.add(dbEntity);
}
cursor.close();
return list;
}
public DbEntity findEntityById(int id) {
String[] columns = {"id", "p_id", "province", "c_id", "city", "d_id", "district", "address", "attr"};
String sql = "select * from " + TABLE_NAME + " where id=" + id;
Cursor cursor = mDatabase.rawQuery(sql, new String[]{});
DbEntity dbEntity = null;
while (cursor.moveToNext()) {
dbEntity = new DbEntity();
dbEntity.setId(cursor.getInt(cursor.getColumnIndex(columns[0])));
dbEntity.setP_id(cursor.getInt(cursor.getColumnIndex(columns[1])));
dbEntity.setProvince(cursor.getString(cursor.getColumnIndex(columns[2])));
dbEntity.setC_id(cursor.getInt(cursor.getColumnIndex(columns[3])));
dbEntity.setCity(cursor.getString(cursor.getColumnIndex(columns[4])));
dbEntity.setD_id(cursor.getInt(cursor.getColumnIndex(columns[5])));
dbEntity.setDistrict(cursor.getString(cursor.getColumnIndex(columns[6])));
dbEntity.setAddress(cursor.getString(cursor.getColumnIndex(columns[7])));
dbEntity.setAttr(cursor.getString(cursor.getColumnIndex(columns[8])));
}
cursor.close();
return dbEntity;
}
}
三、使用初始化
DBUtils dbUtils=new DBUtils(this);
SQLiteDatabase db=dbUtils.getReadableDatabase();
dbUtils.setDb(db);