diff --git a/framework/yii/db/oci/ColumnSchema.php b/framework/yii/db/oci/ColumnSchema.php
new file mode 100644
index 0000000..9436c78
--- /dev/null
+++ b/framework/yii/db/oci/ColumnSchema.php
@@ -0,0 +1,92 @@
+<?php
+namespace yii\db\oci;
+
+class ColumnSchema extends \yii\db\ColumnSchema
+{
+
+    /**
+     * Initializes the column with its DB type and default value.
+     * This sets up the column's PHP type, size, precision, scale as well as default value.
+     * 
+     * @param string $dbType
+     *            the column's DB type
+     * @param mixed $defaultValue
+     *            the default value
+     */
+    public function extract($dbType, $defaultValue)
+    {
+        $this->dbType = $dbType;
+        $this->extractType($dbType);
+        $this->extractLimit($dbType);
+        if ($defaultValue !== null)
+            $this->extractDefault($defaultValue);
+    }
+
+    /**
+     * Extracts the PHP type from DB type.
+     * 
+     * @param string $dbType
+     *            DB type
+     * @return string
+     */
+    protected function extractOraType($dbType)
+    {
+        if (strpos($dbType, 'FLOAT') !== false)
+            return 'double';
+        
+        if (strpos($dbType, 'NUMBER') !== false || strpos($dbType, 'INTEGER') !== false) {
+            if (strpos($dbType, '(') && preg_match('/\((.*)\)/', $dbType, $matches)) {
+                $values = explode(',', $matches[1]);
+                if (isset($values[1]) and (((int) $values[1]) > 0))
+                    return 'double';
+                else
+                    return 'integer';
+            } else
+                return 'double';
+        } else
+            return 'string';
+    }
+
+    /**
+     * Extracts the PHP type from DB type.
+     * 
+     * @param string $dbType
+     *            DB type
+     */
+    protected function extractType($dbType)
+    {
+        $this->type = $this->extractOraType($dbType);
+    }
+
+    /**
+     * Extracts size, precision and scale information from column's DB type.
+     * 
+     * @param string $dbType
+     *            the column's DB type
+     */
+    protected function extractLimit($dbType)
+    {
+        if (strpos($dbType, '(') && preg_match('/\((.*)\)/', $dbType, $matches)) {
+            $values = explode(',', $matches[1]);
+            $this->size = $this->precision = (int) $values[0];
+            if (isset($values[1]))
+                $this->scale = (int) $values[1];
+        }
+    }
+
+    /**
+     * Extracts the default value for the column.
+     * The value is typecasted to correct PHP type.
+     * 
+     * @param mixed $defaultValue
+     *            the default value obtained from metadata
+     */
+    protected function extractDefault($defaultValue)
+    {
+        if (stripos($defaultValue, 'timestamp') !== false) {
+            $this->defaultValue = null;
+        } else {
+            $this->defaultValue = $this->typecast($defaultValue);
+        }
+    }
+}
diff --git a/framework/yii/db/oci/QueryBuilder.php b/framework/yii/db/oci/QueryBuilder.php
new file mode 100644
index 0000000..ac3aebb
--- /dev/null
+++ b/framework/yii/db/oci/QueryBuilder.php
@@ -0,0 +1,78 @@
+<?php
+namespace yii\db\oci;
+
+use yii\db\Exception;
+use yii\base\InvalidParamException;
+
+/**
+ * QueryBuilder is the query builder for Oracle databases.
+ * 
+ */
+class QueryBuilder extends \yii\db\QueryBuilder
+{
+
+    private $sql;
+
+    public function build($query)
+    {
+        // var_dump($query);exit;
+        $params = $query->params;
+		$clauses = [ 
+				$this->buildSelect ( $query->select, $query->distinct, $query->selectOption ),
+				$this->buildFrom ( $query->from ),
+				$this->buildJoin ( $query->join, $params ),
+				$this->buildWhere ( $query->where, $params ),
+				$this->buildGroupBy ( $query->groupBy ),
+				$this->buildHaving ( $query->having, $params ),
+				$this->buildUnion ( $query->union, $params ),
+				$this->buildOrderBy ( $query->orderBy ) 
+		// $this->buildLimit($query->limit, $query->offset),
+		
+        ;
+        // var_dump( [implode($this->separator, array_filter($clauses)), $params]);exit;
+        $this->sql = implode($this->separator, array_filter($clauses));
+        
+        if (! is_null($query->limit) && ! is_null($query->offset)) {
+            $this->sql = $this->buildLimit($query->limit, $query->offset);
+        }
+        return [
+            $this->sql,
+            $params
+        ];
+        // return [implode($this->separator, array_filter($clauses)), $params];
+    }
+
+    public function buildLimit($limit, $offset)
+    {
+        // var_dump($limit >= 0);
+        // var_dump($offset);exit;
+        // var_dump($limit, $offset);
+        if (($limit < 0) && ($offset < 0)) {
+            return $this->sql;
+        }
+        $filters = array();
+        if ($offset > 0) {
+            $filters[] = 'rowNumId > ' . (int) $offset;
+        }
+        
+        if ($limit >= 0) {
+            $filters[] = 'rownum <= ' . (int) $limit;
+        }
+        
+        if (count($filters) > 0) {
+            $filter = implode(' and ', $filters);
+            $filter = " WHERE " . $filter;
+        } else {
+            $filter = '';
+        }
+        
+        $sql = <<<EOD
+WITH USER_SQL AS ({$this->sql}),
+	PAGINATION AS (SELECT USER_SQL.*, rownum as rowNumId FROM USER_SQL)
+SELECT *
+FROM PAGINATION
+{$filter}
+EOD;
+        return $sql;
+    }
+}
diff --git a/framework/yii/db/oci/Schema.php b/framework/yii/db/oci/Schema.php
new file mode 100644
index 0000000..2830faf
--- /dev/null
+++ b/framework/yii/db/oci/Schema.php
@@ -0,0 +1,364 @@
+<?php
+namespace yii\db\oci;
+
+use yii\db\TableSchema;
+use yii\db\oci\ColumnSchema;
+
+/**
+ * Schema is the class for retrieving metadata information from an Oracle database.
+ * 
+ */
+
+class Schema extends \yii\db\Schema
+{
+
+    private $_defaultSchema = '';
+
+    public function createQueryBuilder()
+    {
+        return new QueryBuilder($this->db);
+    }
+
+    public function quoteTableName($name)
+    {
+        if (strpos($name, '.') === false) {
+            return $this->quoteSimpleTableName($name);
+        }
+        $parts = explode('.', $name);
+        foreach ($parts as $i => $part) {
+            $parts[$i] = $this->quoteSimpleTableName($part);
+        }
+        return implode('.', $parts);
+    }
+
+    public function quoteSimpleTableName($name)
+    {
+        return '"' . $name . '"';
+        // return $name;
+    }
+
+    public function quoteColumnName($name)
+    {
+        if (($pos = strrpos($name, '.')) !== false) {
+            $prefix = $this->quoteTableName(substr($name, 0, $pos)) . '.';
+            $name = substr($name, $pos + 1);
+        } else {
+            $prefix = '';
+        }
+        return $prefix . ($name === '*' ? $name : $this->quoteSimpleColumnName($name));
+    }
+
+    public function quoteSimpleColumnName($name)
+    {
+        return '"' . $name . '"';
+        // return $name;
+    }
+
+    public function loadTableSchema($name)
+    {
+        $table = new TableSchema();
+        $this->resolveTableNames($table, $name);
+        // $this->findPrimaryKeys($table);
+        if ($this->findColumns($table)) {
+            // $this->findForeignKeys($table);
+            $this->findConstraints($table);
+            return $table;
+        }
+    }
+
+    /**
+     * Resolves the table name and schema name (if any).
+     *
+     * @param TableSchema $table
+     *            the table metadata object
+     * @param string $name
+     *            the table name
+     */
+    protected function resolveTableNames($table, $name)
+    {
+        $parts = explode('.', str_replace('"', '', $name));
+        if (isset($parts[1])) {
+            $table->schemaName = $parts[0];
+            $table->name = $parts[1];
+        } else {
+            $table->name = $parts[0];
+        }
+        
+        if ($table->schemaName === null) {
+            $table->schemaName = $this->getDefaultSchema();
+        }
+    }
+
+    /**
+     *
+     * @return string default schema.
+     */
+    public function getDefaultSchema()
+    {
+        if (! strlen($this->_defaultSchema)) {
+            $this->setDefaultSchema(strtoupper($this->db->username));
+        }
+        
+        return $this->_defaultSchema;
+    }
+
+    /**
+     *
+     * @param string $schema
+     *            default schema.
+     */
+    public function setDefaultSchema($schema)
+    {
+        $this->_defaultSchema = $schema;
+    }
+
+    public function getLastInsertID($sequenceName = '')
+    {
+        if ($this->db->isActive) {
+            $sql = "select {$sequenceName}.currval from dual";
+            return $this->db->createCommand($sql)->queryScalar();
+        } else {
+            throw new InvalidCallException('DB Connection is not active.');
+        }
+    }
+
+    /**
+     * Collects the table column metadata.
+     *     
+     */
+    protected function findColumns($table)
+    {
+        $schemaName = $table->schemaName;
+        $tableName = $table->name;
+        
+        $sql = <<<EOD
+SELECT a.column_name, a.data_type ||
+    case
+        when data_precision is not null
+            then '(' || a.data_precision ||
+                    case when a.data_scale > 0 then ',' || a.data_scale else '' end
+                || ')'
+        when data_type = 'DATE' then ''
+        when data_type = 'NUMBER' then ''
+        else '(' || to_char(a.data_length) || ')'
+    end as data_type,
+    a.nullable, a.data_default,
+    (   SELECT D.constraint_type
+        FROM ALL_CONS_COLUMNS C
+        inner join ALL_constraints D on D.OWNER = C.OWNER and D.constraint_name = C.constraint_name
+        WHERE C.OWNER = B.OWNER
+           and C.table_name = B.object_name
+           and C.column_name = A.column_name
+           and D.constraint_type = 'P') as Key,
+    com.comments as column_comment
+FROM ALL_TAB_COLUMNS A
+inner join ALL_OBJECTS B ON b.owner = a.owner and ltrim(B.OBJECT_NAME) = ltrim(A.TABLE_NAME)
+LEFT JOIN user_col_comments com ON (A.table_name = com.table_name AND A.column_name = com.column_name)
+WHERE
+    a.owner = '{$schemaName}'
+	and (b.object_type = 'TABLE' or b.object_type = 'VIEW')
+	and b.object_name = '{$tableName}'
+ORDER by a.column_id
+EOD;
+        
+        try {
+            $columns = $this->db->createCommand($sql)->queryAll();
+        } catch (\Exception $e) {
+            return false;
+        }
+        
+        foreach ($columns as $column) {
+            $c = $this->createColumn($column);
+            
+            $table->columns[$c->name] = $c;
+            if ($c->isPrimaryKey) {
+                if ($table->primaryKey === null) {
+                    $table->primaryKey = $c->name;
+                } elseif (is_string($table->primaryKey)) {
+                    $table->primaryKey = array(
+                        $table->primaryKey,
+                        $c->name
+                    );
+                } else {
+                    $table->primaryKey[] = $c->name;
+                }
+                $sql = "select sequence_name
+from user_tables tabs
+join user_triggers trigs
+  on trigs.table_name = tabs.table_name
+join user_dependencies deps
+  on deps.name = trigs.trigger_name
+join user_sequences seqs
+  on seqs.sequence_name = deps.referenced_name
+where tabs.table_name = '{$tableName}'
+ and trigs.triggering_event = 'INSERT'";
+                try {
+                    $seqName = $this->db->createCommand($sql)->queryScalar();
+                } catch (\Exception $e) {
+                    return false;
+                }
+                $table->sequenceName = $seqName;
+                $c->autoIncrement = true;
+            }
+        }
+        return true;
+    }
+
+    protected function createColumn($column)
+    {
+        $c = new ColumnSchema();
+        $c->name = $column['COLUMN_NAME'];
+        $c->allowNull = $column['NULLABLE'] === 'Y';
+        $c->isPrimaryKey = strpos($column['KEY'], 'P') !== false;
+        $c->extract($column['DATA_TYPE'], $column['DATA_DEFAULT']);
+        $c->comment = $column['COLUMN_COMMENT'] === null ? '' : $column['COLUMN_COMMENT'];
+        
+        return $c;
+    }
+
+    protected function findConstraints($table)
+    {
+        $sql = <<<EOD
+		SELECT D.constraint_type as CONSTRAINT_TYPE, C.COLUMN_NAME, C.position, D.r_constraint_name,
+                E.table_name as table_ref, f.column_name as column_ref,
+            	C.table_name
+        FROM ALL_CONS_COLUMNS C
+        inner join ALL_constraints D on D.OWNER = C.OWNER and D.constraint_name = C.constraint_name
+        left join ALL_constraints E on E.OWNER = D.r_OWNER and E.constraint_name = D.r_constraint_name
+        left join ALL_cons_columns F on F.OWNER = E.OWNER and F.constraint_name = E.constraint_name and F.position = c.position
+        WHERE C.OWNER = '{$table->schemaName}'
+           and C.table_name = '{$table->name}'
+           and D.constraint_type <> 'P'
+        order by d.constraint_name, c.position
+EOD;
+        $command = $this->db->createCommand($sql);
+        foreach ($command->queryAll() as $row) {
+            if ($row['CONSTRAINT_TYPE'] === 'R') { // foreign key
+                $name = $row["COLUMN_NAME"];
+                $table->foreignKeys[$name] = array(
+                    $row["TABLE_REF"],
+                    $row["COLUMN_REF"]
+                );
+                /*
+                 * if (isset($table->columns[$name])) { $table->columns[$name]->isForeignKey = true; }
+                 */
+            }
+        }
+    }
+
+    /**
+     * Returns all table names in the database.
+     * 
+     * @param string $schema
+     *            the schema of the tables. Defaults to empty string, meaning the current or default schema.
+     *            If not empty, the returned table names will be prefixed with the schema name.
+     * @return array all table names in the database.
+     */
+    protected function findTableNames($schema = '')
+    {
+        if ($schema === '') {
+            $sql = <<<EOD
+SELECT table_name, '{$schema}' as table_schema FROM user_tables
+EOD;
+            $command = $this->db->createCommand($sql);
+        } else {
+            $sql = <<<EOD
+SELECT object_name as table_name, owner as table_schema FROM all_objects
+WHERE object_type = 'TABLE' AND owner=:schema
+EOD;
+            $command = $this->db > createCommand($sql);
+            $command->bindParam(':schema', $schema);
+        }
+        
+        $rows = $command->queryAll();
+        $names = array();
+        foreach ($rows as $row) {
+            if ($schema === $this->getDefaultSchema() || $schema === '') {
+                $names[] = $row['TABLE_NAME'];
+            } else {
+                $names[] = $row['TABLE_SCHEMA'] . '.' . $row['TABLE_NAME'];
+            }
+        }
+        return $names;
+    }
+
+    /**
+     * Builds a SQL statement for renaming a DB table.
+     * 
+     * @param string $table
+     *            the table to be renamed. The name will be properly quoted by the method.
+     * @param string $newName
+     *            the new table name. The name will be properly quoted by the method.
+     * @return string the SQL statement for renaming a DB table.
+     * @since 1.1.6
+     */
+    public function renameTable($table, $newName)
+    {
+        return 'ALTER TABLE ' . $this->quoteTableName($table) . ' RENAME TO ' . $this->quoteTableName($newName);
+    }
+
+    /**
+     * Builds a SQL statement for changing the definition of a column.
+     * 
+     * @param string $table
+     *            the table whose column is to be changed. The table name will be properly quoted by the method.
+     * @param string $column
+     *            the name of the column to be changed. The name will be properly quoted by the method.
+     * @param string $type
+     *            the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
+     *            into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
+     *            For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
+     * @return string the SQL statement for changing the definition of a column.
+     * @since 1.1.6
+     */
+    public function alterColumn($table, $column, $type)
+    {
+        $type = $this->getColumnType($type);
+        $sql = 'ALTER TABLE ' . $this->quoteTableName($table) . ' MODIFY ' . $this->quoteColumnName($column) . ' ' . $this->getColumnType($type);
+        return $sql;
+    }
+
+    /**
+     * Builds a SQL statement for dropping an index.
+     * 
+     * @param string $name
+     *            the name of the index to be dropped. The name will be properly quoted by the method.
+     * @param string $table
+     *            the table whose index is to be dropped. The name will be properly quoted by the method.
+     * @return string the SQL statement for dropping an index.
+     * @since 1.1.6
+     */
+    public function dropIndex($name, $table)
+    {
+        return 'DROP INDEX ' . $this->quoteTableName($name);
+    }
+
+    /**
+     * Resets the sequence value of a table's primary key.
+     * The sequence will be reset such that the primary key of the next new row inserted
+     * will have the specified value or 1.
+     * 
+     * @param CDbTableSchema $table
+     *            the table schema whose primary key sequence will be reset
+     * @param mixed $value
+     *            the value for the primary key of the next new row inserted. If this is not set,
+     *            the next new row's primary key will have a value 1.
+     * @since 1.1.13
+     */
+    public function resetSequence($table, $value = 1)
+    {
+        $seq = $table->name . "_SEQ";
+        if ($table->sequenceName !== null) {
+            $this->db->createCommand("DROP SEQUENCE " . $seq)->execute();
+            
+            $createSequenceSql = <<< SQL
+create sequence $seq
+start with $value
+increment by 1
+nomaxvalue
+nocache
+SQL;
+            $this->db->createCommand($createSequenceSql)->execute();
+        }
+    }
+}