Error Ora 02256
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EXISTS FROM GROUP BY HAVING IN INSERT INSERT ALL INTERSECT IS NOT NULL IS NULL JOIN LIKE MINUS NOT OR ORDER BY PIVOT REGEXP_LIKE SELECT SUBQUERY TRUNCATE UNION UNION ALL UPDATE WHERE Oracle Advanced Oracle Cursors Oracle Exception Handling Oracle Foreign Keys Oracle Loops/Conditionals Oracle Transactions Oracle Triggers String/Char Functions Numeric/Math Functions Date/Time Functions Conversion Functions Analytic Functions Advanced Functions Oracle / PLSQL: ORA-02256 Error Message Learn the cause and how to resolve the ORA-02256 error message in Oracle. Description When you encounter an ORA-02256 error, the following error message will appear: ORA-02256: number of referencing columns must match referenced columns Cause You tried to reference a table using a unique or primary key, but the columns that you listed did not match the primary key. Resolution The option(s) to resolve this Oracle error are: Option #1 This error can also occur when you try to create a foreign key that references a table, but you've listed different columns in your foreign key that do not match the primary key. To resolve this problem, modify your foreign key to reference the correct column list. For example, if you had tried to execute the following commands. CREATE TABLE supplier ( supplier_id numeric(10) not null, supplier_name varchar2(50) not null, contact_name varchar2(50), CONSTRAINT supplier_pk PRIMARY KEY (supplier_id) ); CREATE TABLE products ( product_id numeric(10) not null, supplier_id numeric(10) not null, CONSTRAINT fk_supplier FOREIGN KEY (supplier_id) REFERENCES supplier (supplier_id, supplier_name) ); You would receive the following error message: Since the primary key on the supplier table uses only the supplier_id column (and not the supplier_name column), you must redefine your foreign key to reference only the supplier_id as follows: CREATE TABLE products ( product_id numeric(10) not null, supplier_id numeric(10) not null, CONSTRAINT fk_supplier FOREIGN KEY (supplier_id) REFERENC
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ORA-02256: number of referencing columns must match referenced columns Oracle Database Tips by Burleson Consulting April 17, 2016 Question: What causes this ORA-02256 error on a "alter table add constraint" for a foreign key: ORA-02256: number of referencing columns must match referenced columns Answer: https://www.techonthenet.com/oracle/errors/ora02256.php The oerr utility shows this for the ORA-02256 error: ORA-02256: number of referencing columns must match referenced columns Cause: The number of columns in the foreign-key referencing list is not equal to the number of columns in the referenced list.Action: Make sure that the referencing columns match the referenced columns. This error can also occur when attempt to add http://www.dba-oracle.com/t_ora_02256_number_of_referenced_columns.htm a foreign key to a table but you have listed different columns in your foreign key that do not match your primary key. Oracle Training from Don Burleson The best on site "Oracle training classes" are just a phone call away! You can get personalized Oracle training by Donald Burleson, right at your shop! Burleson is the American Team Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals. Feel free to ask questions on our Oracle forum. Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications. Errata? Oracle technology is changing and we strive to update our BC Oracle support information. If you find an error or have a suggestion for improving our content, we would appreciate your feedback. Just e-mail: and include the URL for the page. Burleson Consulting TORA-02256 Foreign Keys referencing composite primary keys If this is your first visit, be sure to check out the FAQ by clicking the link http://www.dbasupport.com/forums/showthread.php?63059-SQL-Error-ORA-02256-Foreign-Keys-referencing-composite-primary-keys above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. Results 1 to 4 of 4 Thread: SQL Error: ORA-02256 Foreign Keys referencing composite primary keys Tweet Thread Tools Show Printable Version Email this Page… Subscribe error ora to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 07-03-2013,07:39 PM #1 DBA Struggler View Profile View Forum Posts Junior Member Join Date Apr 2013 Posts 2 SQL Error: ORA-02256 Foreign Keys referencing composite primary keys Hello All, I am struggling and frustrated with the error message that I am getting. I do not error ora 02256 understand what I am doing wrong. The following are my created tables below. I am trying to reference a foreign key in the Registration Table with a Primary Composite Key in the Section Table. I am not sure what I am doing wrong. If anyone can help it is much appreciated. The error message I am receiving is below after the last created table. Create Table Student ( StudentID number (6,0) NOT NULL, Student_Name varchar2 (20) NOT NULL, Constraint Student_PK Primary Key (StudentID) ); Create Table Faculty ( FacultyID number (5,0) NOT NULL, Faculty_Name varchar2 (20) NOT NULL, Constraint Faculty_PK Primary Key (FacultyID) ); Create Table Course ( CourseID varchar2 (10) NOT NULL, Course_Name varchar2 (20) NOT NULL, Constraint Course_PK Primary Key (CourseID) ); Create Table Qualified ( FacultyID number (5,0) NOT NULL, CourseID varchar2 (10) NOT NULL, Date_Qualified varchar2 (10) NOT NULL, Constraint Qualified_PK Primary Key (FacultyID, CourseID), Constraint Qualified_FK1 Foreign Key (FacultyID) references Faculty (FacultyID), Constraint Qualified_FK2 Foreign Key (CourseID) references Course (CourseID) ); Create Table Section ( Section_No number (5,0) NOT N