Foreign Key Restraint Error
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error [closed] up vote 1 down vote favorite 1 I'm trying to insert values in a table with sql server 2012, but i have this error: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Fabricante". The conflict occurred in database "practica", table "dbo.Fabricantes", column 'Codigo'. I just have two tables available. this is the code that i use to create the tables create table Fabricantes( Codigo int drop foreign key mysql identity primary key, Nombre nvarchar (100) not null) create table Articulos( Codigo int identity primary key, Nombre nvarchar (100) not null, Precio int, Fabricante int, constraint FK_Fabricante foreign key (Codigo) references Fabricantes (Codigo)) sql sql-server sql-server-2012 share|improve this question edited Oct 4 '12 at 19:50 Jasper de Vries 4,75532150 asked Oct 4 '12 at 19:17 Raymundo Quintero Obando 112 closed as not a real question by Jimmy Sawczuk, Ben, Sergey K., FelipeAls, PaulG Oct 7 '12 at 10:27 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question. we need information about how the tables relate to each other within the FK. Which fields is it based on? –Beth Oct 4 '12 at 19:23 You defined a contraint on a column that is auto-generated. That won't work like that. You have to change yout table definition –juergen d Oct 4 '12 at 19:24 add a com
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Error 1215 (hy000): Cannot Add Foreign Key Constraint
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#1215 - Cannot Add Foreign Key Constraint
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for Developers MariaDB Contributor Agreement MariaDB Contributor Agreement FAQs Community Ambassadors Events Past Events and Conferences Sponsor Sponsors List of Donors Blog About https://mariadb.org/mariadb-innodb-foreign-key-constraint-errors/ MariaDB Sponsors Governance Logos and Badges MariaDB Trademark Usage Statistics https://www.postgresql.org/docs/9.2/static/ddl-constraints.html Service Providers Maintenance Policy Security Policy Download Learn Get Involved Social Media Getting Started for Developers MariaDB Contributor Agreement MariaDB Contributor Agreement FAQs Community Ambassadors Events Past Events and Conferences Sponsor Sponsors List of Donors Blog HomeGeneralMariaDB: InnoDB foreign key constraint errors foreign key MariaDB: InnoDB foreign key constraint errors 2015-08-07 4 Comments Written by Jan Lindstrom Introduction A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table. The table containing the foreign key is called the child table, and the table containing the candidate add foreign key key is called the referenced or parent table. The purpose of the foreign key is to identify a particular row of the referenced table. Therefore, it is required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value). This is called a referential integrity constraint between the two tables. Because violations of these constraints can be the source of many database problems, most database management systems provide mechanisms to ensure that every non-null foreign key corresponds to a row of the referenced table. Consider following simple example: create table parent ( id int not null primary key, name char(80) ) engine=innodb; create table child ( id int not null, name char(80), parent_id int, foreign key(parent_id) references parent(id) ) engine=innodb; As far as I know, the following storage engines for MariaDB and/or MySQL support foreign keys: InnoDB (both innodb_plugin and
8.2 / 8.3 / 8.4 / 9.0 PostgreSQL 9.2.18 Documentation Prev Up Chapter 5. Data Definition Next 5.3. Constraints Data types are a way to limit the kind of data that can be stored in a table. For many applications, however, the constraint they provide is too coarse. For example, a column containing a product price should probably only accept positive values. But there is no standard data type that accepts only positive numbers. Another issue is that you might want to constrain column data with respect to other columns or rows. For example, in a table containing product information, there should be only one row for each product number. To that end, SQL allows you to define constraints on columns and tables. Constraints give you as much control over the data in your tables as you wish. If a user attempts to store data in a column that would violate a constraint, an error is raised. This applies even if the value came from the default value definition. 5.3.1. Check Constraints A check constraint is the most generic constraint type. It allows you to specify that the value in a certain column must satisfy a Boolean (truth-value) expression. For instance, to require positive product prices, you could use: CREATE TABLE products ( product_no integer, name text, price numeric CHECK (price > 0) ); As you see, the constraint definition comes after the data type, just like default value definitions. Default values and constraints can be listed in any order. A check constraint consists of the key word CHECK followed by an expression in parentheses. The check constraint expression should involve the column thus constrained, otherwise the constraint would not make too much sense. You can also give the constraint a separate name. This clarifies error messages and allows you to refer to the constraint when you need to change it. The syntax is: CREATE TABLE products ( product_no integer, name text, price numeric CONSTRAINT positive_price CHECK (price > 0) ); So, to specify a named constraint, use the key word CONSTRAINT followed by an identifier followed by the constraint definition. (If you don't specify a constraint name in this way, the system chooses a name for you.) A check constraint can also refer to several columns. Say you store a regular price and a discounted price, and you want to ensure that the discounted price is lower than the regular price: CREATE TABLE products ( pro