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**AddRelation( **//relationmanager //[//,updatemode// ,//deletemode// ,//relatedkey//]// //**), PROTECTED**

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| **AddRelation** | Describes a relationship between this object's primary file (see //Me//) and another file. |
| //relationmanager// | The label of the related file's RelationManager object. |
| //updatemode// | A numeric constant, variable, EQUATE, or expression that indicates the referential integrity constraint to apply upon updates to the primary file's linking field. Valid constraints are none, clear, restrict, and cascade. If omitted, then //deletemode //and //relatedkey //must also be omitted, and the relationship is unconstrained. |
| //deletemode// | A numeric constant, variable, EQUATE, or expression that indicates the referential integrity constraint to apply upon deletes of the primary file's linking field. Valid constraints are none, clear, restrict, and cascade. If omitted, then //updatemode //and //relatedkey //must also be omitted, and the relationship is unconstrained. |
| //relatedkey// | The label of the related file's linking KEY. If included, the call to AddRelation must be followed by a call to AddRelationLink for each linking component field of the key. If omitted, then //updatemode //and //deletemode //must also be omitted, and the relationship is unconstrained. |

The **AddRelation **method, in conjunction with the AddRelationLink method, describes a relationship between this object's primary file (see //Me//) and another file so that other RelationManager methods can cascade or constrain file operations across the related files when appropriate.

**Implementation:**

You should typically call AddRelation after the Init method is called (or within your derived Init method).

The EQUATEs for //updatemode //and //deletemode //are declared in FILE.INC as follows:

**    ITEMIZE(0),PRE(RI)**

**None     EQUATE     !no action on related files**

**Clear    EQUATE     !clear the linking fields in related files**

**Restrict EQUATE     !disallow the operation if linked records exist**

**Cascade  EQUATE     !update the linking fields in related files, or**

**    END             !delete the linked records in related files**

**Example:**

**Orders    FILE,DRIVER('TOPSPEED'),PRE(ORD),CREATE**

**ByCustomer KEY(ORD:CustNo,ORD:OrderNo),DUP,NOCASE,OPT**

**Record     RECORD,PRE()**

**CustNo      LONG**

**OrderNo     LONG**

**OrderDate   LONG**

**Reference   STRING(24)**

**ShipTo      STRING(32)**

**Shipped     BYTE**

**Carrier     STRING(1)**

**           END**

**          END**

**Items   FILE,DRIVER('TOPSPEED'),PRE(ITEM),CREATE**

**AsEntered  KEY(ITEM:CustNo,ITEM:OrderNo,ITEM:LineNo),NOCASE,OPT,PRIMARY**

**Record     RECORD,PRE()**

**CustNo      LONG**

**OrderNo     LONG**

**LineNo      SHORT**

**ProdCode    SHORT**

**Quantity    SHORT**

**           END**

**          END**

** CODE**

** !program code**

**Relate:Orders.Init PROCEDURE**

** CODE**

**  SELF.AddRelation( Relate:Items,0,0, ITEM:AsEntered )**

**  SELF.AddRelationLink( ORD:CustNo, ITEM:CustNo )**

**  SELF.AddRelationLink( ORD:OrderNo, ITEM:OrderNo )**

**  SELF.AddRelation( Relate:Customer )**

**See Also:**     [[addrelationlink  set linking fields for a relationship .htm|AddRelationLink]], [[init  initialize the relationmanager object .htm|Init]]