#POSTGRESQL INSERT INTO TABLE UPDATE#

Test=# INSERT INTO t_product VALUES (1, 'PostgreSQL consulting', 1) ĮRROR: insert or update on table 't_product' violates foreign key constraint 't_product_currency_id_fkey'ĭETAIL: Key (currency_id)=(1) is not present in table 't_currency'. Let us see if we happen to insert into the product table:

Basically it is a very simple data model. We want to store currencies, products, as well as product descriptions. Location_id int REFERENCES t_location (id),

Product_id int REFERENCES t_product (id), To show the importance of order, we have to create a data model first:Ĭurrency_id int REFERENCES t_currency (id), However, if a foreign key is in place, order starts to matter (at least in a typical scenario but more on that later). If there are no foreign keys, you can insert data into any table in any order. However, foreign keys will introduce some issues which you have to take care of when writing applications. Referential integrity is therefore one of the most important concepts ever invented in IT. The core idea is to prevent your PostgreSQL database from storing inconsistent data by enforcing constraints ensuring the correctness of your tables (at least as far as relations between objects are concerned). In SQL, the concept of foreign keys is an important one that can be found in all professional databases used in the industry. Constraint foreign key integrity postgresql

Postgresql insert into table