pl/sql游戏规则， 做Oracle开发的人员可以作为参考

 

PL/SQL遊戲規則

 

一.    程式編碼

1.      命名原則

(1).程式命名原則: 小於 30 碼 ,小寫,以能表達含義為準,多單詞時首字母大寫.

對象	前綴	對象	前綴
package	pkg_	trigger	trig_
StoreProcedure	sp_	exception	ep_
function	f_
type	typ_

例: pkg_BankTransactions, sp_log

 

(2).程式中對象命名原則: 小於 30 碼 ,小寫,以能表達含意為準,多單詞時首字母大寫.

對象	前綴	對象	前綴
LoclVariables	l_	RelationalTables	rt_
Parameters	p_	NestedTables	nt_
Cursors	cus_
VarrayNames	v_
ObjectTypeNames	o_
NestedTableTypes	n_
ObjectTables	ot_

例: cus_trans

 

2.      書寫格式

(1).關鍵字、保留字、系統包/過程大寫,其他小寫(為表明含義而大小寫混合的除外).

(2).每個代碼塊縮進3個空格.

(3).每條語句一行(太長的可換行,以整齊為原則).

(4).程式段落之間換行.

(5).Insert語句書寫時須加入Column名稱.

 

3.      程式注釋

(1).每支程式開始都需對程式進行說明,以“Rem”注釋,包括以下內容:

a.       NAME(名稱): 程式代號

b.      DESCRIPTION(說明): 對程式的功能作說明

c.       RETURNS(返回值): 如程式有返回值,則描述一下

d.      NOTES(備註): 另外的注釋、限定條件及其他

e.       AUTHOR(作者): 創建人、創建日

f.        MODIFIED(修改記錄): 修改人、修改日、修改內容

g.       其他認為有必要加入的說明.

       (2).程式中有必要說明的段落及變量、參數等,以“--”注釋;儘量不用“/* …… */”.

          例：-- Applies pending transactions in the table TRANSACTIONS to the

-- ACCOUNTS table. Used at regular intervals to update bank

-- accounts without interfering with input of new transactions.

          而非：/* Applies pending transactions in the table TRANSACTIONS to the

                  ACCOUNTS table. Used at regular intervals to update bank

                  accounts without interfering with input of new transactions. */

 

二.    整體架構

 

1.      pkg_bas為公用package,內含用戶使用procedure的記錄、程式異常log、權限設定、公用ASSERT等.

 

2.      pkg_xxx為不同應用建立的package.

 

 

 

 

三.    公用package(pkg_bas)

1.      sp_log

(1).對於一些需記錄用戶使用時間的procedure,可通過sp_log()來寫到下面table:

<<log_call>>
Name	Code	DataType
調用時間	invoking_time	DATE
資料庫用戶	DB_user	VARCHAR2(20)
用戶代號	user_id	VARCHAR2(20)
用戶名稱	user_name	VARCHAR2(30)
程式名稱	procedure_name	VARCHAR2(30)
傳遞參數	parameters	VARCHAR2(500)

 

(2).程式異常時,可通過sp_log()來寫到下面table:

<<log_errors>>
Name	Code	DataType
出錯時間	error_time	DATE
程式名稱	procedure_name	VARCHAR2(30)
錯誤訊息	error_message	VARCHAR2(90)
用戶代號	user_id	VARCHAR2(20)
用戶名稱	user_name	VARCHAR2(30)

 

2.      sp_SetRole

用於特殊權限的設定,如:人事系統中的權限.

 

3.      sp_assert

集中通用的斷言在一個procedure中,如:當用戶想調用無權使用的procedure時,可用它來作統一命名. 不用時可關閉.

 

四.    Procedure樣式

Rem NAME:        pkg_BankTransactions

Rem DESCRIPTION: The following example creates the specification and body for a package

Rem              that contains several procedures and functions that process banking

Rem              transactions.

Rem RETURNS:    

Rem NOTES:      

Rem AUTHOR:     

Rem MODIFIED:   

 

------------------------------------------------------------------------------------------

CREATE PACKAGE pkg_BankTransactions (null) AS

   minimum_balance CONSTANT NUMBER := 100.00;

   PROCEDURE sp10_ApplyTransactions;

   PROCEDURE sp20_EnterTransaction (acct   NUMBER,

                                kind   CHAR,

                                amount NUMBER);

END pkg_BankTransactions;

------------------------------------------------------------------------------------------

CREATE PACKAGE BODY pkg_BankTransactions AS

 

-- Package to input bank transactions 

 

   new_status CHAR(20); -- Global variable to record status

                          -- of transaction being applied. Used

                          -- for update in sp10_ApplyTransactions. 

 

   PROCEDURE sp1000_DoJournalEntry (acct NUMBER, kind CHAR) IS

 

-- Records a journal entry for each bank transaction applied by the sp10_ApplyTransactions

-- procedure. 

 

   BEGIN

      INSERT INTO journal VALUES (acct, kind, sysdate);

         IF kind = 'D' THEN

            new_status := 'Debit applied';

         ELSIF kind = 'C' THEN

            new_status := 'Credit applied';

         ELSE

            new_status := 'New account';

         END IF;

  END sp1000_DoJournalEntry;

------------------------------------------------------------------------------------------

   PROCEDURE sp100_CreditAccount (acct NUMBER, credit NUMBER) IS

 

-- Credits a bank account the specified amount. If the account does not exist, the procedure

-- creates a new account first. 

 

      old_balance NUMBER;

      new_balance NUMBER;

 

   BEGIN

      SELECT balance INTO old_balance FROM accounts

       WHERE acct_id = acct

         FOR UPDATE OF balance; -- Locks account for credit update 

 

      new_balance := old_balance + credit;

      UPDATE accounts SET balance = new_balance

       WHERE acct_id = acct;

      sp1000_DoJournalEntry(acct, 'C');

 

   EXCEPTION

      WHEN NO_DATA_FOUND THEN -- Create new account if not found 

         INSERT INTO accounts (acct_id, balance) VALUES(acct, credit);

         sp1000_DoJournalEntry(acct, 'N');

      WHEN OTHERS THEN -- Return other errors to application 

         new_status := 'Error: ' || SQLERRM(SQLCODE);

   END sp100_CreditAccount;

------------------------------------------------------------------------------------------

   PROCEDURE sp200_DebitAccount (acct NUMBER, debit NUMBER) IS

 

-- Debits an existing account if result is greater than the allowed minimum balance. 

 

      old_balance         NUMBER;

      new_balance         NUMBER;

      insufficient_funds EXCEPTION;

 

   BEGIN

      SELECT balance INTO old_balance FROM accounts

       WHERE acct_id = acct

         FOR UPDATE OF balance;

      new_balance := old_balance - debit;

      IF new_balance >= minimum_balance THEN

         UPDATE accounts SET balance = new_balance

          WHERE acct_id = acct;

         sp1000_DoJournalEntry(acct, 'D');

      ELSE

         RAISE insufficient_funds;

     END IF;

 

   EXCEPTION

      WHEN NO_DATA_FOUND THEN

         new_status := 'Nonexistent account';

      WHEN insufficient_funds THEN

         new_status := 'Insufficient funds'; 

      WHEN OTHERS THEN -- Returns other errors to application  

         new_status := 'Error: ' || SQLERRM(SQLCODE); 

   END sp200_DebitAccount;

------------------------------------------------------------------------------------------

   PROCEDURE sp10_ApplyTransactions IS

 

-- Applies pending transactions in the table TRANSACTIONS to the

-- ACCOUNTS table. Used at regular intervals to update bank

-- accounts without interfering with input of new transactions. 

 

-- Cursor fetches and locks all rows from the TRANSACTIONS

-- table with a status of 'Pending'. Locks released after all

-- pending transactions have been applied. 

 

      CURSOR cus_TransCursor IS

      SELECT acct_id, kind, amount FROM transactions

       WHERE status = 'Pending'

       ORDER BY time_tag

        FOR UPDATE OF status;

 

   BEGIN

      FOR trans IN cus_TransCursor LOOP   -- implicit open and fetch 

         IF trans.kind = 'D' THEN

            sp200_DebitAccount(trans.acct_id, trans.amount);

         ELSIF trans.kind = 'C' THEN

            sp100_CreditAccount(trans.acct_id, trans.amount);

         ELSE

            new_status := 'Rejected';

         END IF;

         -- Update TRANSACTIONS table to return result of applying this transaction. 

         UPDATE transactions SET status = new_status

          WHERE CURRENT OF cus_TransCursor;

      END LOOP ;

      COMMIT; -- Release row locks in TRANSACTIONS table. 

   END sp10_ApplyTransactions;

------------------------------------------------------------------------------------------

   PROCEDURE sp20_EnterTransaction (acct NUMBER, kind CHAR, amount NUMBER) IS

 

-- Enters a bank transaction into the TRANSACTIONS table. A new

-- transaction is always put into this 'queue' before being

-- applied to the specified account by the sp10_ApplyTransactions

-- procedure. Therefore, many transactions can be simultaneously

-- input without interference. 

 

   BEGIN

      INSERT INTO transactions VALUES (acct, kind, amount, 'Pending', sysdate);

      COMMIT;

   END sp20_EnterTransaction;

------------------------------------------------------------------------------------------

END pkg_BankTransactions;