Re: many to many relation

From: Tore Halset (halse..vv.ntnu.no)
Date: Mon Dec 11 2006 - 08:46:00 EST

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    Hello.

    On Dec 11, 2006, at 13:01 , marco turchi wrote:

    > I've read the documentation, I created a flattened many-to-many
    > relationship, but any record has been inserted inside the
    > connection table.
    >
    > I have the following tables and relationships:

    Your mapping is wrong. I have fixed it and included it at the bottom
    of this mail.

    Issuing the following java code (almost the same as yours):

             String typeEntity = "myTypeEntity";
             String term = "myTerm";

             DataContext context = DataContext.createDataContext();

             NeEntity entity = (NeEntity) context.newObject(NeEntity.class);
             NeEntityName entityName = (NeEntityName) context.newObject
    (NeEntityName.class);
             entity.setEntityType(typeEntity);
             entityName.setName(term);
             entity.addToEntityNames(entityName);

             context.commitChanges();

    result in the following log:
    INFO QueryLogger: +++ Connecting: SUCCESS.
    INFO QueryLogger: Detected and installed adapter:
    org.apache.cayenne.dba.derby.DerbyAdapter
    INFO QueryLogger: SELECT NEXT_ID FROM AUTO_PK_SUPPORT WHERE
    TABLE_NAME = ? FOR UPDATE [bind: 'NE_ENTITY_NAME']
    INFO QueryLogger: --- transaction started.
    INFO QueryLogger: SELECT NEXT_ID FROM AUTO_PK_SUPPORT WHERE
    TABLE_NAME = ? FOR UPDATE [bind: 'NE_ENTITY']
    INFO QueryLogger: --- will run 3 queries.
    INFO QueryLogger: INSERT INTO NE_ENTITY_NAME (id, name) VALUES (?, ?)
    INFO QueryLogger: [bind: 200, 'myTerm']
    INFO QueryLogger: === updated 1 row.
    INFO QueryLogger: INSERT INTO NE_ENTITY (entityType, id) VALUES (?, ?)
    INFO QueryLogger: [bind: 'myTypeEntity', 200]
    INFO QueryLogger: === updated 1 row.
    INFO QueryLogger: INSERT INTO NE_NAME_RELATION (id_entity,
    id_entity_name) VALUES (?, ?)
    INFO QueryLogger: [bind: 200, 200]
    INFO QueryLogger: === updated 1 row.
    INFO QueryLogger: +++ transaction committed.

      - Tore.

    <?xml version="1.0" encoding="utf-8"?>
    <data-map project-version="2.0">
            <property name="defaultPackage" value="marcoproblem.data"/>
            <db-entity name="NE_ENTITY">
                    <db-attribute name="entityType" type="VARCHAR" length="255"/>
                    <db-attribute name="id" type="INTEGER" isPrimaryKey="true"
    isMandatory="true"/>
            </db-entity>
            <db-entity name="NE_ENTITY_NAME">
                    <db-attribute name="id" type="INTEGER" isPrimaryKey="true"
    isMandatory="true"/>
                    <db-attribute name="name" type="VARCHAR" length="150"/>
            </db-entity>
            <db-entity name="NE_NAME_RELATION">
                    <db-attribute name="id_entity" type="INTEGER" isPrimaryKey="true"
    isMandatory="true"/>
                    <db-attribute name="id_entity_name" type="INTEGER"
    isPrimaryKey="true" isMandatory="true"/>
            </db-entity>
            <obj-entity name="NeEntity" className="marcoproblem.data.NeEntity"
    dbEntityName="NE_ENTITY">
                    <obj-attribute name="entityType" type="java.lang.String" db-
    attribute-path="entityType"/>
            </obj-entity>
            <obj-entity name="NeEntityName"
    className="marcoproblem.data.NeEntityName"
    dbEntityName="NE_ENTITY_NAME">
                    <obj-attribute name="name" type="java.lang.String" db-attribute-
    path="name"/>
            </obj-entity>
            <db-relationship name="toNameRelation" source="NE_ENTITY"
    target="NE_NAME_RELATION" toDependentPK="true" toMany="true">
                    <db-attribute-pair source="id" target="id_entity"/>
            </db-relationship>
            <db-relationship name="toNameRelation" source="NE_ENTITY_NAME"
    target="NE_NAME_RELATION" toDependentPK="true" toMany="true">
                    <db-attribute-pair source="id" target="id_entity_name"/>
            </db-relationship>
            <db-relationship name="toEntity" source="NE_NAME_RELATION"
    target="NE_ENTITY" toMany="false">
                    <db-attribute-pair source="id_entity" target="id"/>
            </db-relationship>
            <db-relationship name="toEntityName" source="NE_NAME_RELATION"
    target="NE_ENTITY_NAME" toMany="false">
                    <db-attribute-pair source="id_entity_name" target="id"/>
            </db-relationship>
            <obj-relationship name="entityNames" source="NeEntity"
    target="NeEntityName" deleteRule="Nullify" db-relationship-
    path="toNameRelation.toEntityName"/>
            <obj-relationship name="entities" source="NeEntityName"
    target="NeEntity" deleteRule="Nullify" db-relationship-
    path="toNameRelation.toEntity"/>
    </data-map>



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