Cursor cursor: (loop operation of batch data)

Declare Cursor  Stus_cur  Is  Select* FromStudents; -- defines the cursor and assigns a value (is cannot be used separately from cursor) cur_stu students % Rowtype; -- Define rowtype Begin Open  Stus_cur; -- Enable cursor Loop-- Loop Exit  WhenStus_cur % Notfound; -- Cyclic Condition Fetch  Stus_cur  IntoCur_stu; -- the cursor value is assigned to rowtype dbms_output.put_line (cur_stu.name); -- output End  Loop; -- End the loop Close  Stus_cur; -- Close the cursor End;

PLSQL is a process-oriented language. This type of language also has c, COBOL, etc. The common feature of this type of language is that only one piece of data can be processed at a time, and the object returned by database SQL is a set, in this way, problems may occur when you directly use the PLSQL program. In this environment, a cursor is displayed. The cursor is actually a memory address and points to the result set queried by SQL, when necessary, fetch data [fetch] One by one based on the cursor until all data is obtained.

Cursor  Mininter1  Is SelectT1.rm _ interface, t1.rm _ merchno, Min(Getexp (t1.rr _ id, tradeamount, '','', '0') minexp FromT_r_merchant T1 WhereT1.rm _ interface = interid1 OrT1.rm _ interface = interid2 Group  ByT1.rm _ interface, t1.rm _ merchno; Open  Mininter1; Loop Exit  When  Mininter1% Notfound; Fetch  Mininter1  IntoNresult, tmpmchno, minexp; icount: = mininter1 % Rowcount; End  Loop; Close  Mininter1;

 

 

 

 

 

 

 

 

 

 

 

 

Cursor cursor: (loop operation of batch data)