TYPE info_index IS TABLE OF VARCHAR(20) INDEX BY PLS_INTEGER;告訴我這段代碼的意思

这段代码定义了一个类型info_index，它是一个关联数组（也称为索引表或哈希表），可以通过整数类型的索引（即PLS_INTEGER）来访问其中的元素。每个元素是一个长度为20的字符串（即VARCHAR(20)）。这个类型的定义允许在程序中创建类似于数组的结构，其中每个元素可以使用整数索引进行访问和操作。

相关问题

plsql is table of

在Oracle PL/SQL中，`TABLE OF`是一种特殊的数据类型，它表示一个数组或集合，可以存储一系列相同类型的元素。当你声明一个`IS TABLE OF`类型的变量时，实际上是创建了一个动态的、可变大小的容器，用于存储一系列指定类型的值。例如：

DECLARE
  TYPE employee_records_type IS TABLE OF VARCHAR2(50) INDEX BY PLS_INTEGER; -- 定义一个员工记录类型，每个元素最多50字符，按整数下标索引
  v_employee_records employee_records_type;
BEGIN
  v_employee_records("John") := 'Developer'; -- 存储一条记录
  v_employee_records(2) := 'Manager'; -- 另存一条记录
  FOR i IN v_employee_records.first..v_employee_records.last LOOP
    DBMS_OUTPUT.PUT_LINE(i || ': ' || v_employee_records(i));
  END LOOP;
END;

这里，`v_employee_records`就是一个`IS TABLE OF VARCHAR2`类型的变量，可以存储多条字符串，并通过整数下标访问它们。在循环中，你可以遍历整个数组。

CREATE TABLE CUSTOMER ( CustomerID NUMBER PRIMARY KEY, Name VARCHAR2(20), Address VARCHAR2(20), PhoneNumber VARCHAR2(20), Email VARCHAR2(30), LoyaltyStatus VARCHAR2(20) ); CREATE TABLE ORDERS ( OrderID NUMBER PRIMARY KEY, OrderDate DATE, OrderStatus VARCHAR2(20), TotalCost NUMBER, CustomerID NUMBER, CONSTRAINT FK_ORDER_CUSTOMER FOREIGN KEY (CustomerID) REFERENCES CUSTOMER(CustomerID) ); CREATE TABLE PRODUCT ( ProductID NUMBER PRIMARY KEY, ProductName VARCHAR2(20), Description VARCHAR2(20), Price NUMBER, Category VARCHAR2(20) ); CREATE TABLE ORDERS_DETAILS ( OrderDetailID NUMBER PRIMARY KEY, OrderID NUMBER, ProductID NUMBER, ProductName VARCHAR2(20), Price NUMBER, Quantity NUMBER, Subtotal NUMBER, CONSTRAINT FK_ORDER_DETAILS_ORDER FOREIGN KEY (OrderID) REFERENCES ORDERS(OrderID), CONSTRAINT FK_ORDER_DETAILS_PRODUCT FOREIGN KEY (ProductID) REFERENCES PRODUCT(ProductID) ); CREATE TABLE STORE ( StoreID NUMBER PRIMARY KEY, StoreName VARCHAR2(20), Location VARCHAR2(20), HoursOfOperation VARCHAR2(20) ); CREATE TABLE INVENTORY ( ProductID NUMBER, StoreID NUMBER, QuantityOnHand NUMBER, ReorderPoint NUMBER, PRIMARY KEY (ProductID, StoreID), CONSTRAINT FK_INVENTORY_PRODUCT FOREIGN KEY (ProductID) REFERENCES PRODUCT(ProductID), CONSTRAINT FK_INVENTORY_STORE FOREIGN KEY (StoreID) REFERENCES STORE(StoreID) ); CREATE TABLE "TRANSACTION" ( TransactionID NUMBER PRIMARY KEY, TransactionDate DATE, TransactionType VARCHAR2(20), TotalAmount NUMBER, CustomerID NUMBER, CONSTRAINT FK_TRANSACTION_CUSTOMER FOREIGN KEY (CustomerID) REFERENCES CUSTOMER(CustomerID) ); CREATE TABLE TRANSACTION_DETAILS ( TransactionDetailID NUMBER PRIMARY KEY, TransactionID NUMBER, ProductID NUMBER, ProductName VARCHAR2(20), Price NUMBER, Quantity NUMBER, Subtotal NUMBER, CONSTRAINT FK_TRANSACTION_DETAILS_TRANSACTION FOREIGN KEY (TransactionID) REFERENCES "TRANSACTION"(TransactionID), CONSTRAINT FK_TRANSACTION_DETAILS_PRODUCT FOREIGN KEY (ProductID) REFERENCES PRODUCT(ProductID) ); CREATE TABLE EMPLOYEE ( EmployeeID NUMBER PRIMARY KEY, Name VARCHAR2(20), Address VARCHAR2(20), PhoneNumber VARCHAR2(20), Email VARCHAR2(30), Position VARCHAR2(20) ); CREATE TABLE SALARY ( EmployeeID NUMBER, StartDate DATE, SalaryAmount NUMBER, EndDate DATE, PRIMARY KEY (EmployeeID, StartDate), CONSTRAINT FK_SALARY_EMPLOYEE FOREIGN KEY (EmployeeID) REFERENCES EMPLOYEE(EmployeeID) ); CREATE TABLE SHIFT ( ShiftID NUMBER PRIMARY KEY, StartTime TIMESTAMP, EndTime TIMESTAMP, StoreID NUMBER, EmployeeID NUMBER, CONSTRAINT FK_SHIFT_EMPLOYEE FOREIGN KEY (EmployeeID) REFERENCES EMPLOYEE(EmployeeID), CONSTRAINT FK_SHIFT_STORE FOREIGN KEY (StoreID) REFERENCES STORE(StoreID) ); 加密Price和PhoneNumber

可以使用 Oracle 提供的 DBMS_CRYPTO 包来加密 Price 和 PhoneNumber 字段。首先需要创建一个加密密钥，然后使用该密钥对数据进行加密和解密。

以下是加密 Price 和 PhoneNumber 字段的示例 SQL 代码：

-- 创建密钥
DECLARE
key_raw RAW(32) := utl_raw.cast_to_raw('my_secret_key');
encryption_type PLS_INTEGER := dbms_crypto.ENCRYPT_AES256 + dbms_crypto.CHAIN_CBC + dbms_crypto.PAD_PKCS5;
key_handle NUMBER;
BEGIN
key_handle := dbms_crypto.create_key(
key_length => 32,
key_type => dbms_crypto.TYPE_AES256,
key_source => key_raw
);
END;
/

-- 加密 Price 字段
UPDATE PRODUCT
SET Price = dbms_crypto.encrypt(
src => to_char(Price),
typ => encryption_type,
key => key_handle
);

-- 加密 PhoneNumber 字段
UPDATE CUSTOMER
SET PhoneNumber = dbms_crypto.encrypt(
src => PhoneNumber,
typ => encryption_type,
key => key_handle
);

注意，在实际应用中，需要妥善保管密钥，确保数据的安全性。