Is it possible to create entity to postgres foreign table? Always when I want to create doctrine:migration:diff migration tool generate sql to delete foreign tables becouse the entity isn't created for this table.
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I have created a table but forgot to create an association for foreign key in sequelize.
Now I want to update a column to set as a foreign key..
Can we do that in sequelize?
I have a requirement of deleting records from the Postgres database tables.
We have a Customer table which is the main table, this table contains a primary key which is used in so many other tables as a FOREIGN KEY, I want to delete one of the customers as well as its reference used in other tables. Is there any way to delete the customer from main table as well as from other tables which contains foreign key.
Thanks in Advance.
In the other tables, you want a cascading delete foreign key reference. You can create one in the database using:
alter table othertable add constraint fk_othertable_customerid
foreign key (customerid) references customers(customerid)
on delete cascade;
Note: This assumes that customerid is the name of the column in both tables and that it is already defined in the other tables.
A cascading foreign key constraint does exactly what you specify. When a row is deleted in the reference table, then all related rows are deleted.
If you already have foreign key constraints on customerid, then drop the existing constraint and add the cascading version.
Hi i have one doubt in postgres. In database have 100 tables . few tables have primary key and foreign key relationship and few tables do not have relationship.
Here I want delete all tables useing delete statement.
When I tried delete statement for all tables that time getting error pk and fk violation.
How will delete fk first and pk tables.
Could you tell me how to write a query to achieve this task I postgres.
You can try the CASCADE option.
https://www.postgresql.org/docs/current/ddl-constraints.html -> item 5.3.5
In JPA project, when I generate tables for entities I can't see any table foreign key constraints created on database side.
I concluded that JPA cannot create table foreign key constraints in database and that referential integrity is enforced in JPA (on application side) and not by database.
Can someone confirm if this is so?
According to the JPA 2.2 specification, the persistence manager should create foreign key constraints. For example in the case of a one-to-one mapping:
Assuming that:
Entity A references a single instance of Entity B.
Entity B references a single instance of Entity A.
Entity A is specified as the owner of the relationship.
The following mapping defaults apply:
Entity A is mapped to a table named A.
Entity B is mapped to a table named B.
Table A contains a foreign key to table B. The foreign key column name is formed as the concatenation of the following: the name of the relationship property or field of entity A; the name of the primary key column in table B. The foreign key column has the same type as the primary key of table B and there is a unique key constraint on it.
Entity database model insert project and than create database.But some tables not created.
I added primary key and created it again but the same tables didn't occur with primary key.
So 2 tables(don’t created 2 tables) set a primary key.But I dont solve a problem.
How to solve problem in entity?