sqlite3 ，请教这个视图该如何写？

-- 厂家表

CREATE TABLE Vender (

    Id   INTEGER     PRIMARY KEY AUTOINCREMENT,

    Name CHAR( 32 )  NOT NULL

                     UNIQUE,

    Show BOOLEAN     NOT NULL

                     DEFAULT ( TRUE )

);



-- 产品类型表

CREATE TABLE ProductType (

    Id   INTEGER     PRIMARY KEY AUTOINCREMENT,

    Name CHAR( 32 )  NOT NULL

                     UNIQUE

);



-- 产品表

CREATE TABLE Product (

    Id    INTEGER PRIMARY KEY AUTOINCREMENT,

    V_Id  INTEGER NOT NULL

                  REFERENCES Vender ( Id ) ON DELETE NO ACTION

                                           ON UPDATE CASCADE,

    PT_Id INTEGER NOT NULL

                  REFERENCES ProductType ( Id ) ON DELETE NO ACTION

                                                ON UPDATE CASCADE,

    Show BOOLEAN  NOT NULL

                  DEFAULT ( TRUE ),

    UNIQUE ( V_Id, PT_Id )

);



-- 产品价格表

CREATE TABLE ProductValue (

    P_Id  INTEGER NOT NULL

                  REFERENCES Product ( Id ) ON DELETE NO ACTION

                                            ON UPDATE CASCADE,

    Value NUMERIC NOT NULL,

    Date  DATE    NOT NULL,

    UNIQUE ( P_Id, Date )

);