supertype

How to define a Doctrine mappedSuperclass using XML or YAML instead of annotation mapping

由 久未见 提交于 2020-03-05 03:26:57
问题 The following script comes from https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/inheritance-mapping.html#mapped-superclasses, and was only changed to include a second sub-class. It is my understanding that MappedSuperclassBase cannot exist by itself but must be extended by one and only one sub-class (i.e. either EntitySubClassOne or EntitySubClassTwo ), and is the same concept as supertype/subtype for SQL. Agree? How is a super/sub type defined using either YAML or XML

isAnnotationPresent() return false when used with super type reference in Java

由 淺唱寂寞╮ 提交于 2020-01-22 14:45:06
问题 I m trying to get the annotation details from super type reference variable using reflection, to make the method accept all sub types. But isAnnotationPresent() returning false . Same with other annotation related methods. If used on the exact type, output is as expected. I know that annotation info will be available on the Object even I m referring through super type. @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE}) public @interface Table { String name(); } @Table(name =

How do I apply subtypes into an SQL Server database?

由 拟墨画扇 提交于 2019-12-30 00:36:19
问题 I am working on a program in which you can register complaints. There are three types of complaints: internal (errors from employees), external (errors from another company) and supplier (errors made by a supplier). They hold different data which cannot be shared. I currently have 4 tables (complaint, employee, company and supplier). Here's a visualisation of the tables: I have a basic understanding of subtypes but I cannot seem to translate them from an ERD into an actual SQL Server database

Implications of Supertype and Subtype

由 好久不见. 提交于 2019-12-25 05:12:07
问题 Is it bad to implement supertype and subtype to the entire data in a database? I need some advice on this before moving to this direction... For instance, I have these tables as objects and they are related, users pages images entities table as the supertype entity_id entity_type 1 page 2 page 3 user 4 user 5 image 6 image users table user_id entity_id 1 3 2 4 pages table page_id entity_id 1 1 2 2 images table image_id entity_id 1 5 2 6 here is the table to map images table with entities

What is a supertype method?

由 こ雲淡風輕ζ 提交于 2019-12-20 10:54:31
问题 I have googled couple of times but still can't understand the supertype method. Can anyone please explain what is this? 回答1: There is a notion of supertype and subtype in OOPS, In java this kind of relationship is implemented by inheritance i.e. using extends keyword: class A {} // super class class B extends A {} //sub class Any member (fields, methods) declared in super class is to be called supertype. Therefore in above context if class A has method like class A { void set() } Set is

isAnnotationPresent() return false when used with super type reference in Java

由 喜夏-厌秋 提交于 2019-12-03 14:35:23
I m trying to get the annotation details from super type reference variable using reflection, to make the method accept all sub types. But isAnnotationPresent() returning false . Same with other annotation related methods. If used on the exact type, output is as expected. I know that annotation info will be available on the Object even I m referring through super type. @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE}) public @interface Table { String name(); } @Table(name = "some_table") public class SomeEntity { public static void main(String[] args) { System.out.println

What is a supertype method?

由 筅森魡賤 提交于 2019-12-03 00:35:08
I have googled couple of times but still can't understand the supertype method. Can anyone please explain what is this? navyad There is a notion of supertype and subtype in OOPS, In java this kind of relationship is implemented by inheritance i.e. using extends keyword: class A {} // super class class B extends A {} //sub class Any member (fields, methods) declared in super class is to be called supertype. Therefore in above context if class A has method like class A { void set() } Set is supertype method for class B . However, notice that if there is another class say C : class C { void set()

How do I apply subtypes into an SQL Server database?

由 别说谁变了你拦得住时间么 提交于 2019-11-30 04:06:26
I am working on a program in which you can register complaints. There are three types of complaints: internal (errors from employees), external (errors from another company) and supplier (errors made by a supplier). They hold different data which cannot be shared. I currently have 4 tables (complaint, employee, company and supplier). Here's a visualisation of the tables: I have a basic understanding of subtypes but I cannot seem to translate them from an ERD into an actual SQL Server database, or at least in this scenario. This is roughly how the 4 tables look (irrelevant attributes omitted):

Cannot reference “X” before supertype constructor has been called, where x is a final variable

由 限于喜欢 提交于 2019-11-27 17:47:22
Consider the following Java class declaration: public class Test { private final int defaultValue = 10; private int var; public Test() { this(defaultValue); // <-- Compiler error: cannot reference defaultValue before supertype constructor has been called. } public Test(int i) { var = i; } } The code will not compile, with the compiler complaining about the line I've highlighted above. Why is this error happening and what's the best workaround? Amr Bekhit The reason why the code would not initially compile is because defaultValue is an instance variable of the class Test , meaning that when an

Cannot reference “X” before supertype constructor has been called, where x is a final variable

由 馋奶兔 提交于 2019-11-26 19:05:02
问题 Consider the following Java class declaration: public class Test { private final int defaultValue = 10; private int var; public Test() { this(defaultValue); // <-- Compiler error: cannot reference defaultValue before supertype constructor has been called. } public Test(int i) { var = i; } } The code will not compile, with the compiler complaining about the line I've highlighted above. Why is this error happening and what's the best workaround? 回答1: The reason why the code would not initially
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