refs 数据类型之间的 db2 比较

Question

我已经定义了这个触发器来控制删除后对象之间的引用，这样架构中就不会保留“悬空引用”：

CREATE TRIGGER gestionRefTransferencia
BEFORE DELETE ON Corriente
REFERENCING OLD AS O
FOR EACH ROW MODE DB2SQL
BEGIN
    UPDATE Transferencia SET Cuenta_receptora = NULL WHERE Cuenta_receptora = O.oid;
END@

但是db2返回如下错误：

“操作“=”的操作数的数据类型不兼容或可比”

任何想法为什么？不能比较ref数据类型吗？

这是我的架构：

CREATE TYPE Cuenta_udt AS (
    IBAN               VARCHAR(28),
    Saldo              REAL,
    Numero_de_cuenta   BIGINT,
    Fecha_creacion     DATE
) mode DB2SQL;

CREATE TYPE Operacion_udt AS (
    Cod_Num       INTEGER,
    Descripcion   VARCHAR(100),
    Hora          INTEGER,
    Fecha         DATE,
    Cantidad      REAL,
    Cuenta_IBAN   VARCHAR(28)
) mode DB2SQL;

CREATE TYPE De_ahorro_udt UNDER Cuenta_udt AS (
    Interes         REAL,
    Ultimo_devengo  INTEGER
) mode DB2SQL;

CREATE TYPE Corriente_udt UNDER Cuenta_udt AS (
    Oficina_bancaria_Codigo     INTEGER,
    Oficina_bancaria_Direccion  VARCHAR(100)
) mode DB2SQL;

CREATE TYPE Transferencia_udt UNDER Operacion_udt AS (
    Cuenta_IBAN_receptora   VARCHAR(28),
    Cuenta_receptora        REF(Cuenta_udt)
) mode DB2SQL;

CREATE TABLE Cuenta OF Cuenta_udt (
    REF IS oid USER GENERATED,
    IBAN                        WITH OPTIONS NOT NULL,
    Saldo                       WITH OPTIONS NOT NULL,
    Numero_de_cuenta            WITH OPTIONS NOT NULL,
    Fecha_creacion              WITH OPTIONS NOT NULL,
    CONSTRAINT pk_cuenta PRIMARY KEY(IBAN)
);

CREATE TABLE Operacion OF Operacion_udt (
    REF IS oid USER GENERATED,
    Cod_Num         WITH OPTIONS NOT NULL,
    Hora                    WITH OPTIONS NOT NULL,
    Fecha                   WITH OPTIONS NOT NULL,
    Cantidad                WITH OPTIONS NOT NULL,
    Cuenta_IBAN             WITH OPTIONS NOT NULL,
    CONSTRAINT pk_operacion PRIMARY KEY(Cod_Num),
    FOREIGN KEY (Cuenta_IBAN) REFERENCES Cuenta(IBAN) ON DELETE CASCADE
);

CREATE TABLE Corriente OF Corriente_udt UNDER Cuenta INHERIT SELECT PRIVILEGES (
    FOREIGN KEY (Oficina_bancaria_Codigo, Oficina_bancaria_Direccion) REFERENCES Oficina_bancaria(Codigo, Direccion) ON DELETE SET NULL
);

CREATE TABLE Transferencia OF Transferencia_udt UNDER Operacion INHERIT SELECT PRIVILEGES (
    Cuenta_receptora        WITH OPTIONS SCOPE Cuenta,
    FOREIGN KEY (Cuenta_IBAN_receptora) REFERENCES Cuenta(IBAN) ON DELETE CASCADE
);

Answer 1

要比较两种不同的引用数据类型，请适当地转换它们。

例如，如果您的 CUENTA_UDT 层次结构具有“REF USING BIGINT” 此外，如果您的 OPERACION_UDT 使用“REF USING BIGINT”，那么您的触发器可能如下所示：

CREATE or replace TRIGGER gestionRefTransferencia
BEFORE DELETE ON Corriente
REFERENCING OLD AS O
FOR EACH ROW MODE DB2SQL
BEGIN
         UPDATE Transferencia SET Cuenta_receptora = NULL WHERE cast(Cuenta_receptora as bigint) = cast(O.OID as bigint);
END@

如果两个层次结构的引用类型使用不同的基本类型，则转换/转换为通用基本类型以进行比较。