数据库语言的一些操作

    xiaoxiao2021-12-14  49

    MySQL与sqLite的一些操作 MySQL: 开启服务器:net start mysql 关闭服务器:net stop mysql 登入服务器:mysql -uroot -p123 -hlocalhost > -u  后面跟用户名 > -p  后面跟密码 > -h后面跟IP 查看MySQL数据库编码:SHOW  VARIABLES  LIKE  ‘char%’; 改编码  set  名称=gbk;当前窗口有效 character_set_client character_set_results  在总配置my.ini文件进行配置,一直有效 数据库备份:(备份数据库内容,不是备份数据库)      myslqdump  -u用户名  -p密码  数据库名>生成脚本文件路径 恢复数据:      myslq  -u用户名  -p密码  数据库名<生成脚本文件路径      source  路径 退出服务器:exit 或 quit
    ★数据库语句 查看数据库: SHOW DATABASES 切换(选择要操作的)数据库: USE 数据库名           创建数据库: CREATE DATABASE 数据库名 删除数据库:DROP DATABASE 数据库名 修改数据库编码:ALTER DATABASE 数据库名  CHARACTER SET utf8 进入数据库: USE 数据库名 ★创建表 CREATE TABLE 表名( 列名  列类型,PRIMARY KEY (主键)  AUTO_INCREMENT (主键自增长) 列名  列类型, NOT NULL(非空) UNIQUE  (唯一) … 列名  列类型 ); 查看表:SHOW  TABLES; 查看表结构:  DESC 表名; 删除表:  DROP TABLE 表名; 删除主键:ALTER TABLE 表名  DROP PRIMARY KEY 修改表: 添加列: ALTER  TABLE  表名 ADD ( 列名  列类型, 列名  列类型, … ) ; 修改列类型: ALTER TABLE 表名 MODIFY 列名  新类型; 删除列: ALTER TABLE 表名 DROP 列名; 修改表名称: ALTER TABLE 表名 RENAME  TO 新表名; ALTER  TABLE  表名 ADD —>添加列 MODIFY —>修改列名和列类型 CHANGE  —>修改列名 DROP —>删除列 RENAME  TO —>修改表名
    ★数据库操作语言 ★★★  在数据库中所以的字符串类型,必须使用单引,不能使用双引      查询表记录:SELECT  *  FROM  表名       插入数据:                INSERT  INTO  表名 ( 列名1,列名2,列名3,…)VALUES ( 列值1,列值2,列值3,…) ;       修改数据:           条件运算符:                =、!=、<>, >, <, >=, <=, BETWEEN…AND, IN(…), IS NULL, NOT, OR, AND           改变一个                UPDATE  表名  SET  列名= ‘ 列值 ’  WHERE 列名= ‘ 列值 ’           改变多个                UPDATE  表名  SET  列名= ‘ 列值 ’  WHERE 列名= ‘ 列值 ’ OR 列名= ‘ 列值 ’       删除数据:            DELETE  FROM  表名  WHERE  条件;            DELETE  FROM  表名   (删除全部数据)       查询表记录:           SELECT  *  FROM  表名           SELECT  列1,列2...   FROM  表名           去除完全相同的重复行           SELECT  DISTINCT  列名  FROM  表名      模糊查询  关键字  LIKE           SELECT  *  FROM  表名 WHERE  列名 LIKE ‘_%_'           select  列           from     表名           where     条件           group by     组           having     组条件           order  by   列名  排序(DESC降序)(ASC升序)           AVG平均值           COUNT(*)数量
    * 1.创建数据表     create table userinfo(id integer primary key autoincrement, username varchar(20), password varchar(20)) * 2.插入数据         insert into userinfo(username, password) values ("lisi","abcd") * 3.删除         delete from userinfo  删除表中所有数据         delete from userinfo where id=4         delete from userinfo where username='lisi' or password='abcde' * 4.修改         update userinfo set password="1234",username='zhangfei' where id=8 * 5.查询         select * from userinfo;         select * from userinfo where id=9         select password,id from userinfo where username='zhangsan'
    创建数据库继承  SQLiteOpenHelper   BlackListOpenHelper helper= new BlackListOpenHelper(context);      获取自己创建的数据库的db   SQLiteDatabase db = helper.getWritableDatabase(); 获取已有的数据库的db //1.数据库路径  2.  3.模式读写 SQLiteDatabase db=SQLiteDatabase.openDatabase(file.getAbsolutePath(), null, SQLiteDatabase.OPEN_READONLY); /**  * 骚扰拦截的数据库CDUQ  *  * @author Administrator  *  */ public class BlackListDao {      BlackListOpenHelper helper;      public BlackListDao(Context context) {            super();            helper = new BlackListOpenHelper(context);      }      /**       * 数据库添加       *       * @param number       * @param type       * @return       */      public long insert(String number, int type) {            SQLiteDatabase db = helper.getWritableDatabase();            ContentValues values = new ContentValues();            values.put(BlackListDB.TableBlackList.COLUMN_NUMBER, number);            values.put(BlackListDB.TableBlackList.COLUMN_TYPE, type);            long insert = db.insert(BlackListDB.TableBlackList.TABLE_NAME, null,                      values);            db.close();            return insert;      }      /**       * 数据库的删除       *       * @param number       * @return       */      public int delete(String number) {            SQLiteDatabase db = helper.getWritableDatabase();            int delete = db.delete(BlackListDB.TableBlackList.TABLE_NAME,                      BlackListDB.TableBlackList.COLUMN_NUMBER + "=?",                      new String[] { number });            db.close();            return delete;      }      /**       * 数据库的修改       *       * @param number       * @param type       * @return       */      public int update(String number, int type) {            SQLiteDatabase db = helper.getWritableDatabase();            ContentValues values = new ContentValues();            values.put(BlackListDB.TableBlackList.COLUMN_TYPE, type);            int update = db.update(BlackListDB.TableBlackList.TABLE_NAME, values,                      BlackListDB.TableBlackList.COLUMN_NUMBER + "=?",                      new String[] { number });            db.close();            return update;      }      /**       * 数据库的查询       *       * @return       */      public List<BlackListBean> query() {            List<BlackListBean> list = new ArrayList<BlackListBean>();            SQLiteDatabase db = helper.getReadableDatabase();            Cursor cursor = db.query(BlackListDB.TableBlackList.TABLE_NAME, null,                      null, null, null, null, null);            while (cursor.moveToNext()) {                 String number = cursor.getString(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_NUMBER));                 int type = cursor.getInt(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_TYPE));                 BlackListBean blackListBean = new BlackListBean(number, type);                 list.add(blackListBean);            }            cursor.close();            db.close();            return list;      }      /**       * 数据库的分页查询       *       * @return       */      public List<BlackListBean> query(int limit, int offset) {            List<BlackListBean> list = new ArrayList<BlackListBean>();            SQLiteDatabase db = helper.getReadableDatabase();            String sql = "select * from " + BlackListDB.TableBlackList.TABLE_NAME                      + " limit ? offset ?";            Cursor cursor = db.rawQuery(sql,                      new String[] { limit + "", offset + "" });            // Cursor cursor = db.query(BlackListDB.TableBlackList.TABLE_NAME, null,            // null, null, null, null, null);            while (cursor.moveToNext()) {                 String number = cursor.getString(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_NUMBER));                 int type = cursor.getInt(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_TYPE));                 BlackListBean blackListBean = new BlackListBean(number, type);                 list.add(blackListBean);            }            cursor.close();            db.close();            return list;      }      /**       * 判断短信是否拦截       *       * @param number       * @return       */      public boolean query(String number) {            SQLiteDatabase db = helper.getReadableDatabase();            String[] projection = { BlackListDB.TableBlackList.COLUMN_TYPE };            Cursor cursor = db.query(BlackListDB.TableBlackList.TABLE_NAME,                      projection, BlackListDB.TableBlackList.COLUMN_NUMBER + "=?",                      new String[] { number }, null, null, null);            try {                 if (cursor.moveToNext()) {                      int type = cursor                                 .getInt(cursor                                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_TYPE));                      return type != 0;                 }                 return false;            } finally {                 cursor.close();                 db.close();            }      }      /**       * 判断电话是否拦截       *       * @param number       * @return       */      public boolean queryPhone(String number) {            SQLiteDatabase db = helper.getReadableDatabase();            String[] projection = { BlackListDB.TableBlackList.COLUMN_TYPE };            Cursor cursor = db.query(BlackListDB.TableBlackList.TABLE_NAME,                      projection, BlackListDB.TableBlackList.COLUMN_NUMBER + "=?",                      new String[] { number }, null, null, null);            try {                 if (cursor.moveToNext()) {                      int type = cursor                                 .getInt(cursor                                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_TYPE));                      return type != 1;                 }                 return false;            } finally {                 cursor.close();                 db.close();            }      } }
    分页数据库的创建 public interface BlackListDB {      /**       * 数据库的名称       */      String DB_NAME = "black_list.db";      /**       * 数据库版本       */      int DB_VERSION=1;      public interface TableBlackList{            String TABLE_NAME="blacklist";            String COLUMN_ID = "_id";            String COLUMN_NUMBER = "number";            String COLUMN_TYPE = "type";            String TABLE_SQL="CREATE TABLE "+TABLE_NAME+" ( "            +COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "            +COLUMN_NUMBER+" VARCHAR  UNIQUE, "            +COLUMN_TYPE+" INTEGER)";      } } 分页查找 数据库的查询      public List<BlackListBean> query(int limit, int offset) {            List<BlackListBean> list = new ArrayList<BlackListBean>();            SQLiteDatabase db = helper.getReadableDatabase();            String sql = "select * from " + BlackListDB.TableBlackList.TABLE_NAME                      + " limit ? offset ?";            Cursor cursor = db.rawQuery(sql,                      new String[] { limit + "", offset + "" });            // Cursor cursor = db.query(BlackListDB.TableBlackList.TABLE_NAME, null,            // null, null, null, null, null);            while (cursor.moveToNext()) {                 String number = cursor.getString(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_NUMBER));                 int type = cursor.getInt(cursor                           .getColumnIndex(BlackListDB.TableBlackList.COLUMN_TYPE));                 BlackListBean blackListBean = new BlackListBean(number, type);                 list.add(blackListBean);            }            cursor.close();            db.close();            return list;      }
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