写存储过程中涉及到一些游标的问题（There are some vernier issues involved in writing stored procedures）.docVIP

写存储过程中涉及到一些游标的问题（There are some vernier issues involved in writing stored procedures） Write stored procedures that involve some cursors I remember when I went to school to learn programming in PB, Joe teacher told us a lot about this aspect of a lot of content, said the cursor is useful, I never think so, that was when I was a student do things too simple, just put the function implementation, access to the data quantity is small, less involved in the database data. Ok then listen to the teacher, study the seriously, otherwise you must regret now. Programming languages are interlinked, let me learn ORACLE database programming is easier to get started on this. SQL is the language used to access ORACLE databases, and PL/SQL extends and enhances the functionality of SQL, which also introduces stronger programming logic. PL/SQL supports the DML command and SQL transaction control statements. DDL is not supported in PL/SQL, which means that a table or any other object cannot be created in PL/SQL program blocks. A better PL/SQL program design is to use an internal build package like DBMS_SQL in PL/SQL blocks or EXECUTE the EXECUTE IMMEDIATE command to create dynamic SQL to EXECUTE the DDL commands, and the PL/SQL compiler guarantees object references and user privileges. We will discuss various DDL and TCL statements for accessing ORACLE databases. The query The SELECT statement is used to query data from the database, when using the SELECT statement in PL/SQL, should be used together with the INTO clause, the return value of a query is given in the INTO clause variables, variable declaration is in DELCARE. The SELECT INTO syntax is as follows: SELECT [DISTICT | ALL] {* | column [, column,... } INTO (variable [, variable,...] | record) The FROM {table | (sub - query)} [alias] The WHERE... The SELECT statement in PL/SQL returns only one row of data. If you have more than one row of data, then use the explicit cursor (the discussion of the cursor we will be doing later), an