orm

问题 We have got a requirement for multiple schemas in Hibernate. In our project, we need to connect to multiple schemas based on the username and password. But how to configure multiple schemas in Hibernate? Please let me know if there's a way. 回答1: Thanks to Hibernate Multitenancy support, you can easily do that as follows: The following examples can be found in the Hibernate ORM documentation folder. Each schema can be a tenant, so you only need to provide a tenant identifier to the Hibernate

问题 I need to map a OneToMany relationship in hibernate, with the JPA annotations, in which is involved a weak entity. For example Table orders: CREATE TABLE orders( idorder serial NOT NULL, note varchar(30), CONSTRAINT orders_pkey PRIMARY KEY (idorder) ) Table OrderItems: CREATE TABLE orderitems( idorder integer NOT NULL, iditem serial NOT NULL, qnt integer, CONSTRAINT orderitems_pk PRIMARY KEY (idorder, iditem), CONSTRAINT fk_orderitems FOREIGN KEY (idorder) REFERENCES orders (idorder) MATCH

问题 I am struggling to understand the right way to implement association mapping between two entities from different bounded contexts using Doctrine 2. Suppose that there are two "User" and "Post" entities that belong to "User" and "Content" bounded contexts, respectively. There is also a "User" concept in "Content" context that determines the author of a "Post" through a Many-To-One association. Therefore, "User" in "Content" context is simply a value object containing the user id. My question

问题 I am trying to migrate a SQL database using sqlAlchemy and Alembic. I would like to make simple migration scripts directly in Python code, and not by using Alembic CLI, as described in the docs. I only found this SO question on this topic: Using Alembic API from inside application code Using this question + Flask-Alembic source code, I tried these simple commands. engine is linked to my db & metadata contains the information for the migration. I think I am very close, and the solution should

问题 I am trying to migrate a SQL database using sqlAlchemy and Alembic. I would like to make simple migration scripts directly in Python code, and not by using Alembic CLI, as described in the docs. I only found this SO question on this topic: Using Alembic API from inside application code Using this question + Flask-Alembic source code, I tried these simple commands. engine is linked to my db & metadata contains the information for the migration. I think I am very close, and the solution should

问题 How this SQL query can be translated to Django ORM statement? SELECT field1, field2, field3 FROM table1 WHERE field1 NOT IN (SELECT 2_field1 FROM table2); Kindly help! :) ps table1 and table2 not bounded with ForeignKey or ManyToMany 回答1: Using two QuerySets, as shown in the docs. inner_qs = table2.objects.all() results = table1.objects.exclude(field1__in=inner_qs) 来源： https://stackoverflow.com/questions/14105660/select-values-which-not-in-another-table-with-django

问题 How this SQL query can be translated to Django ORM statement? SELECT field1, field2, field3 FROM table1 WHERE field1 NOT IN (SELECT 2_field1 FROM table2); Kindly help! :) ps table1 and table2 not bounded with ForeignKey or ManyToMany 回答1: Using two QuerySets, as shown in the docs. inner_qs = table2.objects.all() results = table1.objects.exclude(field1__in=inner_qs) 来源： https://stackoverflow.com/questions/14105660/select-values-which-not-in-another-table-with-django

问题 I'm trying to associate tables in such a way that: A group has many documents A document belongs to a group A group belongs to an user An user has many groups When i try to list all from table 'Group' including 'User', throws an error saying that User is not associated to Group. My models: Document.js const Document = conn.define('document', { title: { type: Sequelize.TEXT, allowNull: false }, content: { type: Sequelize.TEXT, allowNull: false }, footer: { type: Sequelize.TEXT, } }) Document

问题 I have pretty much an identical issue as Dependency injection with custom Doctrine 2 hydrator, but I need to inject a service into a custom data type , not into a hydrator. The solution in the referenced question is relies on duplicating and modifying doctrine source code as Doctrine initializes the classes itself. Hopefully another approach is viable to custom data types? This is for a Symfony3 application, if there could be some magic to be applied there. 回答1: Per the comments in the

问题 I have pretty much an identical issue as Dependency injection with custom Doctrine 2 hydrator, but I need to inject a service into a custom data type , not into a hydrator. The solution in the referenced question is relies on duplicating and modifying doctrine source code as Doctrine initializes the classes itself. Hopefully another approach is viable to custom data types? This is for a Symfony3 application, if there could be some magic to be applied there. 回答1: Per the comments in the