存储过程学习笔记

1.首先mysql 中的 '分隔符' 是分号(;)

所以在创建存储过程的时候，要先重新定义一下分隔符。这样，存储过程中的语句才不会被当成正常的语句执行。

DELIMITER //
DROP PROCEDURE IF EXISTS test_cursor //
create procedure getAllTypesOfCards(in cardId long, in userId long, in classId long, in cardType int, in isNew boolean)
begin
declare userIdTmp long;
declare DONE int;

declare userIdCur cursor for 
select user1_id as userid from user_relation_table where relation = 'FRIEND' and user2_id = userId 
 union select user2_id as userid from user_relation_table where relation = 'FRIEND' and user1_id = userId;

DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET DONE = 1;
open userIdCur;
REPEAT
fetch userIdCur into userIdTmp;
if isNew = true then
    select * from card_table where cardId < id and state = 0 and (`type` = cardType or class_id = classId or user_id = userIdTmp)
    order by id desc limit 10;
else 
    select * from card_table where cardId > id and state = 0 and (`type` = cardType or class_id = classId or user_id = userIdTmp)
    order by id desc limit 10;
end if;
UNTIL DONE 
END REPEAT;
close userIdCur;
end;//

DELIMITER ;
call getAllTypesOfCards(129427,163,1,1,false);

delimiter //
create procedure getSelfOrFrdsPicVoice(in userId long, in picVoiceId long)
begin
declare userIdTmp long;
declare DONE int;

declare userIdCur cursor for
select user1_id as userid from user_relation_table where relation = 'FRIEND' and user2_id = userId 
 union select user2_id as userid from user_relation_table where relation = 'FRIEND' and user1_id = userId;

declare continue handler for SQLSTATE '02000' set DONE = 1;
open userIdCur;
repeat
fetch userIdCur into userIdTmp;
select id,pic_id,publish_time,user_id,update_time from pic_voice_table 
where id < picVoiceId and (user_id = userId or user_id = userIdTmp) 
order by id desc limit 10;
until done
end repeat;
close userIdCur;
end;//

存储过程定义的参数有三种，in,out,inout。in的话，在过程内部是不能被改动的，out的话是能被改动的，并且外部也是可以获得的，inout是内部可以改动，外部也可以获得。

我这里用到了游标(cursor)，我的理解是类似于结果集，里面存了查询语句查询出来的多条结果（我这里说的肯定很不专业），通过fetch 去遍历，fetch cursor_name into xxx,类似于for(xxx : cursor_name)

即可以用cursor这个游标，去遍历每一条结果集，再进行另外一个操作。

结果集必须打开(open cursor_name)，再循环(repeat)，也得定义一个让循环结束的变量，符合结果end repeat,并close cursor

//删除存储过程

DROP PROCEDURE IF EXISTS 'procedure_name'

//查看存储过程

SHOW CREATE PROCEDURE procedure_name

 JDBC调用存储过程代码如下

Connection conn = null;
        CallableStatement callStmt = null;
        ResultSet rs = null;
        List<Card> cards = new ArrayList<Card>();
        //cardId,userId,classId,cardType,isNew
        String sql = "call getAllTypesOfCards(?,?,?,?,?)";
        try {
            conn = JdbcUtils.getConnection();
            callStmt = conn.prepareCall(sql);
            callStmt.setLong(1, cardId);
            callStmt.setLong(2, userId);
            callStmt.setLong(3, classId);
            callStmt.setInt(4, 1);//card type
            callStmt.setBoolean(5, isNew);
            rs = callStmt.executeQuery();
            while(rs.next()){
                Card card = new Card();
                long id = rs.getLong("id");
                String title = rs.getString("title");
                long createTime = rs.getLong("create_time");
//                long classId = rs.getLong("class_id");
                long updateTime = rs.getLong("update_time");
                int scope = rs.getInt("scope");
                int discuss_count = rs.getInt("discuss_count");
                String userName = rs.getString("user_name");
                int type = rs.getInt("type");
                card.setId(id);
                card.setTitle(title);
                card.setCreateTime(createTime);
                card.setClassId(classId);
                card.setUserId(userId);
                card.setUpdateTime(updateTime);
                card.setScope(scope);
                card.setDiscussCount(discuss_count);
                card.setUserName(userName);
                card.setType(type);
                cards.add(card);
            }
        } catch (SQLException e) {
            throw new SQLRunTimeException(e);
        }finally{
            JdbcUtils.free(rs, callStmt, conn);
        }