创建一个触发器， 当商品表中插入一行数据时，触发器对 数据的正确性进行验证。数据验证规则如下: 1)商品名称、规格型号和计量单位不能为空，商品名称不超过100 字符且不能包含@#$这三个字符; 2)商品单价为大于0 的数值型数据; 3)商品大类编码是Categories表中合法 存在; 4)商品小类编码是CategoryTree表中合法存在的，5)供应商编码是Suppliers表中合法存在的。

好的，根据您的要求，我可以帮您编写以下SQL Server的触发器代码：

CREATE TRIGGER trg_validate_product
ON Products
AFTER INSERT
AS
BEGIN
    -- Check if the product name, specifications and measure unit are not empty and the name does not contain @#$ characters
    IF EXISTS (SELECT * FROM inserted WHERE ISNULL(Name,'')='' OR ISNULL(Specifications,'')='' OR ISNULL(MeasureUnit,'')='' OR CHARINDEX('@',Name)>0 OR CHARINDEX('#',Name)>0 OR CHARINDEX('$',Name)>0 OR LEN(Name)>100)
    BEGIN
        RAISERROR('Product name, specifications and measure unit cannot be empty and the name cannot contain @#$ characters and should not exceed 100 characters.',16,1)
        ROLLBACK TRANSACTION
        RETURN
    END

    -- Check if the product price is greater than 0
    IF EXISTS (SELECT * FROM inserted WHERE ISNULL(Price,0)<=0)
    BEGIN
        RAISERROR('Product price should be greater than 0.',16,1)
        ROLLBACK TRANSACTION
        RETURN
    END

    -- Check if the product category code exists in Categories table
    IF EXISTS (SELECT * FROM inserted i LEFT JOIN Categories c ON i.CategoryCode=c.CategoryCode WHERE c.CategoryCode IS NULL)
    BEGIN
        RAISERROR('Product category code is not valid.',16,1)
        ROLLBACK TRANSACTION
        RETURN
    END

    -- Check if the product subcategory code exists in CategoryTree table
    IF EXISTS (SELECT * FROM inserted i LEFT JOIN CategoryTree ct ON i.SubCategoryCode=ct.SubCategoryCode WHERE ct.SubCategoryCode IS NULL)
    BEGIN
        RAISERROR('Product subcategory code is not valid.',16,1)
        ROLLBACK TRANSACTION
        RETURN
    END

    -- Check if the supplier code exists in Suppliers table
    IF EXISTS (SELECT * FROM inserted i LEFT JOIN Suppliers s ON i.SupplierCode=s.SupplierCode WHERE s.SupplierCode IS NULL)
    BEGIN
        RAISERROR('Supplier code is not valid.',16,1)
        ROLLBACK TRANSACTION
        RETURN
    END
END

这个触发器会对插入到Products表中的数据进行验证，如果数据不符合规则，则会抛出错误并回滚事务，确保数据的正确性。