oracle存储过程游标用法
    English Answer:
    Oracle Stored Procedure Cursor Usage.
    A cursor is a pointer to a set of rows in a database table. It is used to iterate over the rows in a table and retrieve data from them. Cursors are created using the `DECLARE` statement and can be used to perform various operations on data, such as fetching rows, updating rows, or deleting rows.
    To create a cursor, you must first declare a cursor variable. This is done using the following syntax:
    DECLARE cursor_name CURSOR FOR SELECT statement;
    The `SELECT` statement defines the rows that the cursor will point to. Once the cursor has been declared, you can use it to perform various operations on the data in the table.
    The following are some of the most common operations that can be performed on a cursor:
    `FETCH`: Retrieves the next row from the cursor.
    `UPDATE`: Updates the current row in the cursor.
    `DELETE`: Deletes the current row from the cursor.
    `CLOSE`: Closes the cursor and releases the resources that it is using.
    Cursors can be used to improve the performance of your Oracle stored procedures. By using a cursor, you can avoid having to perform multiple queries on the database. This can save time and improve the overall performance of your stored procedure.
    Example.
    The following is an example of a stored procedure that uses a cursor to retrieve data from a table:
oracle手动调用存储过程
    CREATE PROCEDURE get_employees.
    AS.
    BEGIN.
      DECLARE emp_cursor CURSOR FOR.
        SELECT employee_id, first_name, last_name.
        FROM employees;
      OPEN emp_cursor;
      LOOP.
        FETCH emp_cursor INTO emp_id, first_name, last_name;