YII 类库手册

public function __construct($finder,$relation,$parent=null,$id=0)
{
    $this->_finder=$finder;
    $this->id=$id;
    if($parent!==null)
    {
        $this->relation=$relation;
        $this->_parent=$parent;
        $this->model=CActiveRecord::model($relation->className);
        $this->_builder=$this->model->getCommandBuilder();
        $this->tableAlias=$relation->alias===null?$relation->name:$relation->alias;
        $this->rawTableAlias=$this->_builder->getSchema()->quoteTableName($this->tableAlias);
        $this->_table=$this->model->getTableSchema();
    }
    else  // root element, the first parameter is the model.
    {
        $this->model=$relation;
        $this->_builder=$relation->getCommandBuilder();
        $this->_table=$relation->getTableSchema();
        $this->tableAlias=$this->model->getTableAlias();
        $this->rawTableAlias=$this->_builder->getSchema()->quoteTableName($this->tableAlias);
    }

    // set up column aliases, such as t1_c2
    $table=$this->_table;
    if($this->model->getDbConnection()->getDriverName()==='oci')  // Issue 482
        $prefix='T'.$id.'_C';
    else
        $prefix='t'.$id.'_c';
    foreach($table->getColumnNames() as $key=>$name)
    {
        $alias=$prefix.$key;
        $this->_columnAliases[$name]=$alias;
        if($table->primaryKey===$name)
            $this->_pkAlias=$alias;
        else if(is_array($table->primaryKey) && in_array($name,$table->primaryKey))
            $this->_pkAlias[$name]=$alias;
    }
}

public function afterFind()
{
    foreach($this->records as $record)
        $record->afterFindInternal();
    foreach($this->children as $child)
        $child->afterFind();

    $this->children = null;
}

public function beforeFind($isChild=true)
{
    if($isChild)
        $this->model->beforeFindInternal();

    foreach($this->children as $child)
        $child->beforeFind(true);
}

public function buildQuery($query)
{
    foreach($this->children as $child)
    {
        if($child->master!==null)
            $child->_joined=true;
        else if($child->relation instanceof CHasOneRelation || $child->relation instanceof CBelongsToRelation
            || $this->_finder->joinAll || $child->relation->together || (!$this->_finder->baseLimited && $child->relation->together===null))
        {
            $child->_joined=true;
            $query->join($child);
            $child->buildQuery($query);
        }
    }
}

public function count($criteria=null)
{
    $query=new CJoinQuery($this,$criteria);
    // ensure only one big join statement is used
    $this->_finder->baseLimited=false;
    $this->_finder->joinAll=true;
    $this->buildQuery($query);

    $select=is_array($criteria->select) ? implode(',',$criteria->select) : $criteria->select;
    if($select!=='*' && !strncasecmp($select,'count',5))
        $query->selects=array($select);
    else if(is_string($this->_table->primaryKey))
    {
        $prefix=$this->getColumnPrefix();
        $schema=$this->_builder->getSchema();
        $column=$prefix.$schema->quoteColumnName($this->_table->primaryKey);
        $query->selects=array("COUNT(DISTINCT $column)");
    }
    else
        $query->selects=array("COUNT(*)");

    $query->orders=$query->groups=$query->havings=array();
    $query->limit=$query->offset=-1;
    $command=$query->createCommand($this->_builder);
    return $command->queryScalar();
}

public function destroy()
{
    if(!empty($this->children))
    {
        foreach($this->children as $child)
            $child->destroy();
    }
    unset($this->_finder, $this->_parent, $this->model, $this->relation, $this->master, $this->slave, $this->records, $this->children, $this->stats);
}

public function find($criteria=null)
{
    if($this->_parent===null) // root element
    {
        $query=new CJoinQuery($this,$criteria);
        $this->_finder->baseLimited=($criteria->offset>=0 || $criteria->limit>=0);
        $this->buildQuery($query);
        $this->_finder->baseLimited=false;
        $this->runQuery($query);
    }
    else if(!$this->_joined && !empty($this->_parent->records)) // not joined before
    {
        $query=new CJoinQuery($this->_parent);
        $this->_joined=true;
        $query->join($this);
        $this->buildQuery($query);
        $this->_parent->runQuery($query);
    }

    foreach($this->children as $child) // find recursively
        $child->find();

    foreach($this->stats as $stat)
        $stat->query();
}

public function findWithBase($baseRecords)
{
    if(!is_array($baseRecords))
        $baseRecords=array($baseRecords);
    if(is_string($this->_table->primaryKey))
    {
        foreach($baseRecords as $baseRecord)
            $this->records[$baseRecord->{$this->_table->primaryKey}]=$baseRecord;
    }
    else
    {
        foreach($baseRecords as $baseRecord)
        {
            $pk=array();
            foreach($this->_table->primaryKey as $name)
                $pk[$name]=$baseRecord->$name;
            $this->records[serialize($pk)]=$baseRecord;
        }
    }

    $query=new CJoinQuery($this);
    $this->buildQuery($query);
    if(count($query->joins)>1)
        $this->runQuery($query);
    foreach($this->children as $child)
        $child->find();

    foreach($this->stats as $stat)
        $stat->query();
}

public function getColumnPrefix()
{
    if($this->tableAlias!==null)
        return $this->rawTableAlias.'.';
    else
        return $this->_table->rawName.'.';
}

public function getColumnSelect($select='*')
{
    $schema=$this->_builder->getSchema();
    $prefix=$this->getColumnPrefix();
    $columns=array();
    if($select==='*')
    {
        foreach($this->_table->getColumnNames() as $name)
            $columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($this->_columnAliases[$name]);
    }
    else
    {
        if(is_string($select))
            $select=explode(',',$select);
        $selected=array();
        foreach($select as $name)
        {
            $name=trim($name);
            $matches=array();
            if(($pos=strrpos($name,'.'))!==false)
                $key=substr($name,$pos+1);
            else
                $key=$name;
            $key=trim($key,'\'"`');

            if($key==='*')
            {
                foreach($this->_table->columns as $name=>$column)
                {
                    $alias=$this->_columnAliases[$name];
                    if(!isset($selected[$alias]))
                    {
                        $columns[]=$prefix.$column->rawName.' AS '.$schema->quoteColumnName($alias);
                        $selected[$alias]=1;
                    }
                }
                continue;
            }

            if(isset($this->_columnAliases[$key]))  // simple column names
            {
                $columns[]=$prefix.$schema->quoteColumnName($key).' AS '.$schema->quoteColumnName($this->_columnAliases[$key]);
                $selected[$this->_columnAliases[$key]]=1;
            }
            else if(preg_match('/^(.*?)\s+AS\s+(\w+)$/im',$name,$matches)) // if the column is already aliased
            {
                $alias=$matches[2];
                if(!isset($this->_columnAliases[$alias]) || $this->_columnAliases[$alias]!==$alias)
                {
                    $this->_columnAliases[$alias]=$alias;
                    $columns[]=$name;
                    $selected[$alias]=1;
                }
            }
            else
                throw new CDbException(Yii::t('yii','Active record "{class}" is trying to select an invalid column "{column}". Note, the column must exist in the table or be an expression with alias.',
                    array('{class}'=>get_class($this->model), '{column}'=>$name)));
        }
        // add primary key selection if they are not selected
        if(is_string($this->_pkAlias) && !isset($selected[$this->_pkAlias]))
            $columns[]=$prefix.$schema->quoteColumnName($this->_table->primaryKey).' AS '.$schema->quoteColumnName($this->_pkAlias);
        else if(is_array($this->_pkAlias))
        {
            foreach($this->_table->primaryKey as $name)
                if(!isset($selected[$name]))
                    $columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($this->_pkAlias[$name]);
        }
    }

    return implode(', ',$columns);
}

public function getJoinCondition()
{
    $parent=$this->_parent;
    if($this->relation instanceof CManyManyRelation)
    {
        if(!preg_match('/^\s*(.*?)\((.*)\)\s*$/',$this->relation->foreignKey,$matches))
            throw new CDbException(Yii::t('yii','The relation "{relation}" in active record class "{class}" is specified with an invalid foreign key. The format of the foreign key must be "joinTable(fk1,fk2,...)".',
                array('{class}'=>get_class($parent->model),'{relation}'=>$this->relation->name)));

        $schema=$this->_builder->getSchema();
        if(($joinTable=$schema->getTable($matches[1]))===null)
            throw new CDbException(Yii::t('yii','The relation "{relation}" in active record class "{class}" is not specified correctly: the join table "{joinTable}" given in the foreign key cannot be found in the database.',
                array('{class}'=>get_class($parent->model), '{relation}'=>$this->relation->name, '{joinTable}'=>$matches[1])));
        $fks=preg_split('/\s*,\s*/',$matches[2],-1,PREG_SPLIT_NO_EMPTY);

        return $this->joinManyMany($joinTable,$fks,$parent);
    }
    else
    {
        $fks=is_array($this->relation->foreignKey) ? $this->relation->foreignKey : preg_split('/\s*,\s*/',$this->relation->foreignKey,-1,PREG_SPLIT_NO_EMPTY);
        if($this->relation instanceof CBelongsToRelation)
        {
            $pke=$this;
            $fke=$parent;
        }
        else if($this->slave===null)
        {
            $pke=$parent;
            $fke=$this;
        }
        else
        {
            $pke=$this;
            $fke=$this->slave;
        }
        return $this->joinOneMany($fke,$fks,$pke,$parent);
    }
}

public function getPrimaryKeyRange()
{
    if(empty($this->records))
        return '';
    $values=array_keys($this->records);
    if(is_array($this->_table->primaryKey))
    {
        foreach($values as &$value)
            $value=unserialize($value);
    }
    return $this->_builder->createInCondition($this->_table,$this->_table->primaryKey,$values,$this->getColumnPrefix());
}

public function getPrimaryKeySelect()
{
    $schema=$this->_builder->getSchema();
    $prefix=$this->getColumnPrefix();
    $columns=array();
    if(is_string($this->_pkAlias))
        $columns[]=$prefix.$schema->quoteColumnName($this->_table->primaryKey).' AS '.$schema->quoteColumnName($this->_pkAlias);
    else if(is_array($this->_pkAlias))
    {
        foreach($this->_pkAlias as $name=>$alias)
            $columns[]=$prefix.$schema->quoteColumnName($name).' AS '.$schema->quoteColumnName($alias);
    }
    return implode(', ',$columns);
}

public function getTableNameWithAlias()
{
    if($this->tableAlias!==null)
        return $this->_table->rawName . ' ' . $this->rawTableAlias;
    else
        return $this->_table->rawName;
}

public function lazyFind($baseRecord)
{
    if(is_string($this->_table->primaryKey))
        $this->records[$baseRecord->{$this->_table->primaryKey}]=$baseRecord;
    else
    {
        $pk=array();
        foreach($this->_table->primaryKey as $name)
            $pk[$name]=$baseRecord->$name;
        $this->records[serialize($pk)]=$baseRecord;
    }

    foreach($this->stats as $stat)
        $stat->query();

    switch(count($this->children))
    {
        case 0:
            return;
        break;
        case 1:
            $child=reset($this->children);
        break;
        default: // bridge(s) inside
            $child=end($this->children);
        break;
    }

    $query=new CJoinQuery($child);
    $query->selects=array();
    $query->selects[]=$child->getColumnSelect($child->relation->select);
    $query->conditions=array();
    $query->conditions[]=$child->relation->condition;
    $query->conditions[]=$child->relation->on;
    $query->groups[]=$child->relation->group;
    $query->joins[]=$child->relation->join;
    $query->havings[]=$child->relation->having;
    $query->orders[]=$child->relation->order;
    if(is_array($child->relation->params))
        $query->params=$child->relation->params;
    $query->elements[$child->id]=true;
    if($child->relation instanceof CHasManyRelation)
    {
        $query->limit=$child->relation->limit;
        $query->offset=$child->relation->offset;
    }

    $child->beforeFind();
    $child->applyLazyCondition($query,$baseRecord);

    $this->_joined=true;
    $child->_joined=true;

    $this->_finder->baseLimited=false;
    $child->buildQuery($query);
    $child->runQuery($query);
    foreach($child->children as $c)
        $c->find();

    if(empty($child->records))
        return;
    if($child->relation instanceof CHasOneRelation || $child->relation instanceof CBelongsToRelation)
        $baseRecord->addRelatedRecord($child->relation->name,reset($child->records),false);
    else // has_many and many_many
    {
        foreach($child->records as $record)
        {
            if($child->relation->index!==null)
                $index=$record->{$child->relation->index};
            else
                $index=true;
            $baseRecord->addRelatedRecord($child->relation->name,$record,$index);
        }
    }
}

public function runQuery($query)
{
    $command=$query->createCommand($this->_builder);
    foreach($command->queryAll() as $row)
        $this->populateRecord($query,$row);
}