will be the foreign key allows Null values?

Similar Questions

• Oracle cannot validate the composite foreign key when NULLs comes into play

  Hi all

  When a composite foreign key is used in a schema. Oracle does not check the necessary rules correctly, as indicated below.

  create the table parent_tab
  (
  x int,
  int y,
  z int,
  primary key for constraint p_key (x, y)
  );

  create the table child_tab
  (
  x int,
  int y,
  z int,
  Constraint f_key foreign key (x, y) refers to parent_tab (x, y)
  );

  insert into child_tab (x, y, z) values (1, NULL, 4);
  commit;

  Select count(x|| y) from parent_tab;

  0

  
  Select count(x|| y) from child_tab;

  1

  Tom Kyte says the following for an explanation.

  The database is unable to validate a foreign key when it is partially null. To assert the rule MATCH FULL for composite foreign keys, you add a constraint to your table:

  The constraint will ensure that either

  • All columns have NULL value in the foreign key, or
  • None of the columns are set to NULL in the foreign key

  As long as this constraint is in place, your foreign key will work as you probably think that it should.

  However, it does not explain WHY? I mean why Oracle is unable to validate the foreign key when it is partially NULL?

  Concerning

  John Spencer wrote:

  He thinks logically.  You have a composite PK of two columns, so 1, 1 is a valid key, as these are the 1, 2 and 1, 3 and 1.42.  In the child table, you have a line 1, the null value.

  What parent should have the child?

  I wish that it would be logical about this. Unfortunately, Oracle applies different rules in different cases. For example, parent of the value 1, NULL value and 1 child, NULL is not the same as NULL is equal or not equal to null. At the same time, one constraint unique index / unique Treaty, 1, NULL, equal to another 1, NULL NULL treatment as being equal to NULL and don't let several lines with 1, the NULL value.

  SY.

• How can I make sure that changes in a primary key (in the parent table) would also appear directly in the FOREIGN KEY in the child table?

  Forgive my question. I am very new to Oracle.

  How can I make sure that changes in the key primary supplier_id (concerning the supplier table) would also appear directly in the FOREIGN KEY (supplier_id) in the products table?

  Is that not all the primary key and FOREIGN KEY on?

  My paintings:

  I created 2 tables and connect to apply in the data base referential integrity, as I learned.

  CREATE TABLE - parent provider

  (the numeric (10) of supplier_id not null,)

  supplier_name varchar2 (50) not null,

  Contact_Name varchar2 (50).

  CONSTRAINT supplier_pk PRIMARY KEY (supplier_id)

  );

  CREATE TABLE - child products

  (the numeric (10) of product_id not null,)

  supplier_id numeric (10) not null,

  CONSTRAINT fk_supplier

  FOREIGN KEY (supplier_id)

  REFERENCES beg (supplier_id)

  );

  I inserted the following text:

  INSERT INTO provider

  (supplier_id, supplier_name, contact_name)

  VALUES

  (5000, 'Apple', 'first name');

  I expect that the supplier_id (5000) to the provider of the table also appears in the products table under key supplier_id having the same value which is 5000. But this does not happen.

  How to get there?

  Thanks in advance!

  Hello

  What is a foreign key in Oracle?

  A foreign key is a way to ensure referential integrity in your Oracle database. A foreign key means that the values of a table must appear also in another table.

  Ok!??

  What is now the right way to implement referential integrity in your Oracle database that the values of a table must also be included in another table?

  A foreign key referential integrity indeed enfore in ensuring that the value in the child table must have a corresponding parent key (otherwise you will encounter an error, as evidenced by "SomeoneElse"). However, it will never automatically insert a row in the other table.

  If you are looking for a solution that automatically inserts a record in the other table, maybe you should go for triggers:

  See:

  • http://docs.Oracle.com/CD/B28359_01/AppDev.111/b28370/triggers.htm#BABCIBBJ
  • Oracle: Help after HAVING INSERT and AFTER UPDATE triggers

• Drop partition without disabling the foreign key

  Hi all
  
  I have a table parent and child.
  
  Parent table
  
  create the table parent_1
  (identification number,
  create_date date,
  Constraint parent_1_pk001 PRIMARY KEY (id))
  PARTITION OF RANGE (create_date)
  INTERVAL (NUMTODSINTERVAL(1,'DAY'))
  (PARTITION parent_1_part VALUES LESS THAN (January 1, 2010 '));
  
  Child table
  create the table child_1
  (identification number,
  create_date date,
  Constraint child_1_fk001 FOREIGN KEY (id)
  REFERENCES parent_1 (id))
  PARTITION OF RANGE (create_date)
  INTERVAL (NUMTODSINTERVAL(1,'DAY'))
  (PARTITION create_date_part VALUES LESS THAN (January 1, 2010 '));
  
  
  I have problems to delete partition.
  Parent_1
  1 JULY 26, 12
  2 JULY 26, 12
  
  Child_1
  1 JULY 26, 12
  
  ALTER drop partition table CHILD_1 SYS_P274;
  table altered CHILD_1.
  
  ON THE PARENT PARTITION A FALL
  ALTER drop partition table parent_1 SYS_P273;
  
  Error report:
  SQL error: ORA-02266: unique/primary keys in table referenced by foreign keys enabled
  02266 00000 - "unique/primary keys in table referenced by foreign keys enabled.
  * Cause: An attempt was made to truncate a single table or
  primary keys referenced by foreign keys in another table.
  Other unauthorized trades are a drop/truncate partition a
  partitioned table or an ALTER TABLE EXCHANGE PARTITION.
  * Action: Before performing the operations described above, the table, disable the
  constraints foreign key in other tables. You can see what
  constraints are making reference to a table by issuing the following
  command:
  SELECT * FROM USER_CONSTRAINTS WHERE TABLE_NAME = 'tabnam ';
  
  
  PLEASE KNOW IF THERE IS A WAY TO THE PARENT PARTITION DROP WITHOUT TOGGLE FOREIGN CONSTRAINTS
  
  
  Thank you

  SQL Error: ORA-02266: unique/primary keys in table referenced by enabled foreign keys
  02266. 00000 - "unique/primary keys in table referenced by enabled foreign keys"
  *Cause: An attempt was made to truncate a table with unique or
  primary keys referenced by foreign keys enabled in another table.
  Other operations not allowed are dropping/truncating a partition of a
  partitioned table or an ALTER TABLE EXCHANGE PARTITION.
  *Action: Before performing the above operations the table, disable the
  foreign key constraints in other tables. 
  

  You can do until you disable the foreign key constraint

  http://jonathanlewis.WordPress.com/2006/12/10/drop-parent-partition/

  Hope this helps

  Mohamed Houri
  www.hourim.WordPress.com

• Identify the foreign key table

  I have a table that has a few constraints that are foreign keys to other tables (see column FK_ETHNIC below). My naming conventions are consistent so they all start with 'FK_ ". In SQL, how can I find the table that the foreign key column references? I have a process that must find this table and then get all of its columns.
  Thank you!
  
  CREATE TABLE STU_BASE
  (PK_ID VARCHAR2 (32), sys_guid() by default)
  CONSTRAINT pk_stu_base
  KEY ELEMENTARY SCHOOL
  With the HELP of INDEX TABLESPACE sis_express_index
  STORAGE (INITIAL 524288
  NEXT 524288
  PCTINCREASE 0),.
  STUDENT_ID VARCHAR2 (15).
  Fk_stu_base_ethnic FK_ETHNIC VARCHAR2 (32) CONSTRAINT
  REFERENCES
  Ethnic (PK_ID)
  REMOVE THE NULL VALUE;
  
  CREATE TABLE ETHNIC
  (PK_ID VARCHAR2 (32), sys_guid() by default)
  CONSTRAINT pk_ethnic
  KEY ELEMENTARY SCHOOL
  With the HELP of INDEX TABLESPACE sis_express_index
  STORAGE (4096 INITIAL
  NEXT 4096
  PCTINCREASE 0),.
  VARCHAR2 (2) ETHNIC,.
  ETHNIC_DESC VARCHAR2 (30),
  STATE_CODE VARCHAR2 (2),
  FEDERAL_CODE VARCHAR2 (2))

  You could do a self-join with CONSTRAINTS (USER, ALL, s/n) views. You can search a constrainttype of 'R' and you can attach it to itself based on the R_OWNER and R_CONSTRAINT_NAME columns.

  For example:

  SELECT r1.owner      AS child_owner
       , r1.table_name AS child_table
       , r2.owner      AS parent_owner
       , r2.table_name AS parent_table
  FROM   all_constraints r1
  JOIN   all_constraints r2 ON  r2.owner           = r1.r_owner
                            AND r2.constraint_name = r1.r_constraint_name
  WHERE  r1.constraint_type = 'R'
  ;
  

  Published by: Centinul on February 16, 2012 15:36

• Please, I have the following question on the foreign key and the ora-00904

  Thanks in advance!
  
  I created the table:
  
  Create the Department table
  (
  DNAME varchar (15) NOT NULL,
  deptID number (5) NOT NULL,
  Primary key (dname, deptid)
  )
  
  then...
  
  Create table Manager
  (
  MgrID number (10) not null,
  Not null, name varchar (10)
  Start_date date not null,
  Primary key (mgrid),
  
  CONSTRAINT fk_department
  FOREIGN KEY (dname, deptip)
  Department of REFERENCES (dname, deptid)
  )
  
  Trying to create the table with the constraint, it yeilds one:
  
  ORA-00904: "DNAME": invalid identifier
  +.. .with an asterisk under "dname" in line: FOREIGN KEY (dname, deptip) +.
  
  I tried joining my name of the column with quotation marks ("" "); capitalized for consistency; and we tried creating and editing then - all to nothing will do. I also tried to use the user interface with Oracle Express Edition and the moment where I click on create, the same error appears. Could someone help please straighten out me up - was this threat for four days.
  
  Thanks again!

  Hello

  Welcome to the forum!

  Columns that will reference the other table must be declared just like all the other columns; including the names in a FOREIGN KEY constraint is not auotmatically define them.
  It works:

  CREATE TABLE Manager
  (       mgrid          NUMBER (10)     NOT NULL,
       Name          VARCHAR (10)     NOT NULL,
       Start_date      DATE          NOT NULL,
       dname          VARCHAR2 (15),               -- New
       deptid          NUMBER (5),               -- New
  PRIMARY KEY (mgrid),
       --
  CONSTRAINT fk_department
  FOREIGN KEY           (dname, deptid)
  REFERENCES department (dname, deptid)
  );
  

  (assuming that the departments table, you posted, there).

  Is there a reason why you use VARCHAR instead of VARCHAR2?

  In the departments table, do you really need both dname and deptid in the primary key? For example, if you have a line with name = "ACCOUNTING" and deptid = 10; is it possible that you could have another line with deptid = 10 and some different dname, say 'REASEARCH '? It is more common to only have a deptid as primary key and have columns in the foreign key constraints that reference.

• How can I get the data in the foreign key?  PHP/mysql

  I managed to create registration, log-in and results pages appear for accounts of client with PHP/Mysql/Dreamweaver 8. I have another page for more information to be contained in a child table, I used the Insert Wizard to create. I can't make it work. I get either a foreign key cannot be null error or a foreign key constraint.

  If I include the foreign key in the form on the page, I can manually enter the appropriate identification number, and it works. How to automatically enter the id into the foreign key column?

  I got the authentication of users using e-mail, password and user type.

  Thanks for your help

  When someone connects, Dreamweaver creates a session variable called $_SESSION ['MM_Username"]. Use this session variable to create a recordset object to get the ID of the user, who can then be entered in the child table's foreign key field.

  Dreamweaver automatically updates the code for recordsets immediately above the DOCTYPE declaration, then you will need to move above the code for the server behavior insert record. So it must be in the following order:

  1. Recordset to get the user ID
  2. Insert the record to the child table

• Add the foreign key refers to a different schema

  Hello

  We have a database with schemaA and schemaB and we use a data model for schemaA with SQL Data Modeler.

  Our data model is based on SchemaA and we do not want add schemaB or create subview in our current model for schemaB since our dev team do not want schemaB in the model

  We have created a synonym in tableB schemaB shcemaA after granting select them, references to schemaA

  We have added a foreign key on tableA in referencing TableB on schemaB schemaA.

  for example. Add ALTER table tableA foreign constraint key(column-name) references tableB(colum-name)

  So far so good.

  But if we try to produce the DDL for tableA it has not provided the ALTAR of the foreign key that is based on shcmeaB

  We know that we cannot add foreign key on dblinks.

  How can I get the Modeler DDL from SQL data for tableA, including the foreign key

  We appreciate the answers

  Kind regards

  Zafar

  Hi zak,.

  We have created a synonym in tableB schemaB shcemaA after granting select them, references to schemaA

  We have added a foreign key on tableA in referencing TableB on schemaB schemaA.

  You can do it in the database because TableB exists in the database and DB knows its definition, including the existing constraint of PK/UK.

  This is the same model of data Modeler - you must have the definition of the table referenced in order to create the FK that refer to the constraint of PK/UK.

  As it works now (we can change it) you can have modeled for SchemaA and ModelB for SchemaB. Then, you can drag & drop tableB form the Navigator to the diagram of the ModelA and TableB there will exist as an object remote read-only, you can use to create the FK.

  With the help of subviews, DDL generation and configurations of reports, you can display the dev team than objects that they want to see - on the charts in generated DDL and reports.

  Philippe

• How to find the foreign key in pl/sql

  Error from the 1 in the command line:
  DELETE FROM ZKET_SOLE WHERE IID_SOLA = 1
  Error report:
  SQL error: ORA-02292: integrity constraint (IRCKIS. ZKETSTIP_ZKET_FK) violated - book of the foundling
  02292 00000 - 'constraint integrity (s.%s) violated - child notebook found. '
  * Cause: attempted to remove a parent key value that was a stranger
  dependence.
  * Action: remove dependencies first then the parent or disable the constraint.
  
  
  I need to find the foreign key, but I don't know how. I know it must be in the dictionary, but I'm not. I don't have access to the ER model.
  
  THX

  Run this query:

  select * from dba_constraints where owner = 'IRCKIS' and constraint_name = 'ZKETSTIP_ZKET_FK'
  

• SQL statement error INSERT The conflicted with the FOREIGN KEY constraint

  I recently installed a reporting for vmware vsphere software, but I get a SQL error. I opened a request for assistance with vmware, but so far they have not come up with a solution. The error is caused by: com.microsoft.sqlserver.jdbc.SQLServerException: instruction INSERT The conflicted with the FOREIGN KEY constraint 'FK_CB_VSM_NETWORK_VC_ID '. The conflict occurred in database 'VCChargebackVCC02', table "dbo." " CB_VSM_SERVER', column 'VC_ID '. I don't know a lot about SQL, so I'm lost in the extent of troubleshooting is concerned. If anyone has any ideas I'd love to hear them.

  SQL questions are better posed on Technet.  They are better equipped to manage the

  http://social.technet.Microsoft.com/forums/en-us/categories/

• Term plurals changes the name of the foreign key in the relational model

  Hello

  I use a glossary with plurals for entities such as Budget turned to the budgets of the table in the relational model. Unfortunately (for me) it also changes the name of the foreign key. In the related entity, an attribute (for example) is Budget_fiscal year, I expect in the relational model, being the same, but it is transformed into budgets_fiscal_year (budgets in the plural rather than keep him in singular form).

  How can I avoid any change in the attribute names (in the process of engineering in the relational model) but always turn the names of entities from the singular to the plural names for tables?

  Thank you and best regards

  Robert

  Hi Philippe

  Your suggestion 1) works - thank you! budgets_fiscal_year is the attribute of pk exercise in my budget of the entity. It seems a standard behavior of the Data Modeler to compose the UID of the relationship of budgets_fiscal_year (for some reason, this column is not taken the logical model, but the relational model). I would prefer that it be appointed budget_fiscal_year.

  I have not defined any parameter for this (intentionally). But maybe somewhere there by default. Could you tell me where the design parameters in Data Modeler to learn how to configure the definitions mentioned in 2)?

  As I'm always busy with the model of reverse engineering data, I'll wait for DM 4.1.1.888.

  Best regards

  Robert

• Schema import Gets the foreign key number

  Hi all;

  
  

  Scott has a table named rank-> he has primary key-> different tablespace

  Sharma has a table named emp-> he has foreign key-> different tablespace

  $ imp/System Manager queue = refresh_sharma.dmp log = refresh_sharma_imp.log fromuser = touser = sharma sharma

  Import: Free 11.2.0.1.0 - Production Thursday, may 7, 18:35:03-2015

  Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

  Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production

  With partitioning, OLAP, Data Mining and Real Application Testing options

  Export file created by EXPORT: V11.02.00 direct

  import in US7ASCII and AL16UTF16 NCHAR character set

  import server uses WE8MSWIN1252 (possible character set conversion) character set

  Customer export uses the (possible character set conversion) WE8MSWIN1252 character set

  . import of objects in SHARMA SHARMA

  . . import of partition "CONT_EMP": "P1" 4000 imported lines

  . . import of partition "CONT_EMP": "P2" 5000 imported lines

  . . import of partition 'CONT_EMP': 'P3' 5000 imported lines

  . . "DEPT" table import 12 lines imported

  . . import of table 'EMP' 68278 imported lines

  . . importing table "EMP_AUDIT" 4 imported lines

  . . table 'Method' import 68000 lines imported

  . . importing table "EMP_PERS_INFO" 68278 imported lines

  . . importing table "EMP_PROJ_INFO" 68278 imported lines

  . . table 'LOGTAB' import 603 lines imported

  . . table import "PAYROLL" 186282 imported lines

  . . import of table 'of the PROJECT"22 rows imported

  . . importation of "TAB1" 4000000 imported table rows

  . . table import 'TRANSPORT' 0 rows imported

  IMP-00017: statement failed with error ORACLE 1031:

  'ALTER TABLE 'EMP' ADD 'EMP_EMPLEV_C12_FK' OF CONSTRAINT FOREIGN KEY ("EMP_LEVE" '.

  ""L") REFERS TO"SCOTT" CATEGORY"("GRADE_NAME") ENABLE NOVALIDATE.

  IMP-00003: ORACLE error 1031

  ORA-01031: insufficient privileges

  About to activate the constraints...

  IMP-00017: statement failed with error ORACLE 2430:

  ' ALTER TABLE 'EMP' ENABLE CONSTRAINT "EMP_EMPLEV_C12_FK"

  Import completed successfully with warnings.

  30, 31 line number is display error.

  'ALTER TABLE 'EMP' ADD 'EMP_EMPLEV_C12_FK' OF CONSTRAINT FOREIGN KEY ("EMP_LEVE" '.

  ""L") REFERS TO"SCOTT" CATEGORY"("GRADE_NAME") ENABLE NOVALIDATE.

  After the import operation, to recreate the foreign key is the right option. but

  By performing the import operation, how can all I avoid this error dump file or log file?

  I don't want to use constraints = N.
  

  
  

  Thanks in advance

  
  

  You gave * of * SCOTT * at * SHARMA.  The grant received by SHARMA not getting exported when you export SHARMA.  So, it is not imported when you import SHARMA.  If you did an export and import of SCOTT before SHARMA, the award of the cross-schema would have also been imported.  (Subsidies granted by a user are exported with the user, the subsidies received by a user are not exported with the user).

  Hemant K Collette

• Optimize the foreign key for the removal of the cascade constraint.

  Hello

  JDeveloper version: 11.1.2.3.0

  I saw this blog and found something new to me: http://snag.gy/qI6dY.jpg

  Jdeveloper user interface, there is an option to select all tables to select the foreign key and set it for the removal of the waterfall.

  My project is deployed on multiple databases. I wonder where this change is registered. None of the project files is modified.

  Can I make this change (from limitations to the waterfall) for each database that I use?

  Here is the blog where I saw that: http://tompeez.wordpress.com/2013/04/22/master-detail-insertdelete-sample/

  I have my object associations optimized for the removal of the waterfall, but without the option above together, I always get constraint violations...

  Concerning

  Not sure however if you set the option the DOF looks like

  	"EMP_JOB_FK' FOREIGN KEY ('JOB_ID') CONSTRAINT
  	REFERENCES 'HR '. "" SELECT JOBS "("JOB_ID') WE DELETE CASCADE

  If you set the option to cascade for fk Job_id from the employees table.

  Timo

• Rename the foreign key constraint

  Hello
  
  I have table tbl_a with a column a_col1 SEO tbl_b.b_col1
  
  I want to create the name of the foreign key as FK_A_COL1 constraint which is FK_ < COLUMN NAME OF the CHILD >.
  
  Foreign naming key standards does not have the use of the name of the child under the name column.
  
  Is there any other solution/script to achieve this?
  
  Thank you.

  fkeys = model.getFKIndexAssociationSet().toArray();
  for (var i = 0; i;//also can use fk.getTable().getAbbreviation()fkname = "FK_"+fk.getTable().getName();cols = fk.getColumns();for( var k = 0;k
  

• Renaming of the foreign keys in the relational model

  Hello
  
  
  I'm new to the Data Modeler, we use v 3.0.0.66.5 and Oracle 11 g, and I am trying to build a logic and a relational model for a new application.
  
  We always call our primary keys as the ID, this causes me a problem with my names of foreign keys in the relational model, as they show as ID #. Is it possible to add the abbreviated of the table of the foreign key?
  
  Thanks in advance
  
  Sue

  Yes it is.

  Take a look at the tools > preferences, select Data Modeler > naming Standard > model, you can specify the standard you want to use for your foreign key. You can apply this designation to existing models and all new created FK uses the same model. To apply the standard to existing templates, select the relational model in the browser, right-click to display the context menu and select the menu "apply Naming standards... ».

  Sue