catalog/CatalogRelationSchema.hpp - incubator-retired-quickstep - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  **/

 #ifndef QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_
 #define QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_

 #include <cstddef>
 #include <string>
 #include <unordered_map>
 #include <vector>

 #include "catalog/Catalog.pb.h"
 #include "catalog/CatalogAttribute.hpp"
 #include "catalog/CatalogTypedefs.hpp"
 #include "utility/Macros.hpp"
 #include "utility/PtrVector.hpp"
 #include "utility/StringUtil.hpp"

 #include "glog/logging.h"

 namespace quickstep {

 class CatalogDatabase;

 /** \addtogroup Catalog
  *  @{
  */

 /**
  * @brief A relation in a database. This base class only includes information
  *        about the relation's schema. See also CatalogRelation, which augments
  *        this with additional information about physical blocks.
  **/
 class CatalogRelationSchema {
  public:
   typedef std::unordered_map<std::string, CatalogAttribute*>::size_type size_type;
   typedef PtrVector<CatalogAttribute, true>::const_skip_iterator const_iterator;

   /**
    * @brief Reconstruct a relation schema from its serialized Protocol Buffer
    *        form.
    *
    * @param proto The Protocol Buffer serialization of a relation schema,
    *        previously produced by getProto().
    **/
   explicit CatalogRelationSchema(const serialization::CatalogRelationSchema &proto);

   /**
    * @brief Destructor which recursively destroys children.
    **/
   virtual ~CatalogRelationSchema() {}

   /**
    * @brief Serialize the relation schema as Protocol Buffer.
    *
    * @return The Protocol Buffer representation of the relation schema.
    **/
   virtual serialization::CatalogRelationSchema getProto() const;

   /**
    * @brief Check whether a serialization::CatalogRelationSchema is fully-formed
    *        and all parts are valid.
    *
    * @param proto A serialized Protocol Buffer representation of a relation
    *        schema, originally generated by getProto().
    * @return Whether proto is fully-formed and valid.
    **/
   static bool ProtoIsValid(const serialization::CatalogRelationSchema &proto);

   /**
    * @brief Get the parent database.
    *
    * @return Parent database.
    **/
   const CatalogDatabase& getParent() const {
     return *parent_;
   }

   /**
    * @brief Get a mutable pointer to the parent database.
    *
    * @return Parent database.
    **/
   CatalogDatabase* getParentMutable() {
     return parent_;
   }

   /**
    * @brief Get this relation's ID.
    *
    * @return This relation's ID.
    **/
   relation_id getID() const {
     return id_;
   }

   /**
    * @brief Get this relation's name.
    *
    * @return This relation's name.
    **/
   const std::string& getName() const {
     return name_;
   }

   /**
    * @brief Check whether this relation is temporary or permanent.
    *
    * @return True if this relation is temporary, false otherwise.
    **/
   bool isTemporary() const {
     return temporary_;
   }

   /**
    * @brief Check whether an attribute with the given name exists.
    *
    * @param attr_name The name to check for.
    * @return Whether the attribute exists.
    **/
   bool hasAttributeWithName(const std::string &attr_name) const {
     return (attr_map_.find(ToLower(attr_name)) != attr_map_.end());
   }

   /**
    * @brief Check whether an attribute with the given id exists.
    *
    * @param id The id to check for.
    * @return Whether the attribute exists.
    **/
   bool hasAttributeWithId(const attribute_id id) const {
     return (idInRange(id) && !attr_vec_.elementIsNull(id));
   }

   /**
    * @brief Get an attribute by name. The search is case-insensitive.
    *
    * @param attr_name The name to search for.
    * @return The attribute with the given name. NULL if the attribute is not found.
    **/
   const CatalogAttribute* getAttributeByName(const std::string &attr_name) const;

   /**
    * @brief Get a mutable pointer to an attribute by name. The search is case-insensitive.
    *
    * @param attr_name The name to search for.
    * @return The attribute with the given name. NULL if the attribute is not found.
    **/
   CatalogAttribute* getAttributeByNameMutable(const std::string &attr_name);

   /**
    * @brief Get an attribute by ID.
    *
    * @param id The id to search for.
    * @return The attribute with the given ID.
    **/
   const CatalogAttribute* getAttributeById(const attribute_id id) const {
     if (hasAttributeWithId(id)) {
       return &attr_vec_[id];
     } else {
       return nullptr;
     }
   }

   /**
    * @brief Get a mutable pointer to an attribute by ID.
    *
    * @param id The id to search for.
    * @return The attribute with the given ID.
    * @exception AttributeIdNotFound No attribute with the given ID exists.
    **/
   CatalogAttribute* getAttributeByIdMutable(const attribute_id id) {
     if (hasAttributeWithId(id)) {
       return &(attr_vec_[id]);
     } else {
       return nullptr;
     }
   }

   /**
    * @brief Add a new attribute to the relation. If the attribute already has
    *        an ID and/or parent, it will be overwritten.
    *
    * @param new_attr The attribute to be added.
    * @return The id assigned to the attribute.
    * @exception AttributeNameCollision An attribute with the same name as
    *            new_attr is already present in the relation.
    **/
   attribute_id addAttribute(CatalogAttribute *new_attr);

   /**
    * @brief Check whether tuples of the relation are variable-length.
    *
    * @return Whether the relation is variable length (i.e. whether any child
    *         attributes are variable length).
    **/
   bool isVariableLength() const {
     return num_variable_length_attributes_ > 0;
   }

   /**
    * @brief Check how many attributes of the relation are variable-length.
    *
    * @return The number of variable-length attributes in the relation.
    **/
   inline unsigned numVariableLengthAttributes() const {
     return num_variable_length_attributes_;
   }

   /**
    * @brief Get the index of a variable-length attribute among all the
    *        variable-length attributes in this relation.
    *
    * @param id The id of the desired attribute.
    * @return The attribute's index amongst all of the variable-length
    *         attributes, or -1 if the attribute is fixed-length.
    **/
   inline int getVariableLengthAttributeIndex(const attribute_id id) const {
     DCHECK(hasAttributeWithId(id));
     return variable_length_attribute_indices_[id];
   }

   /**
    * @brief Get the maximum length of tuples of this relation, in bytes.
    *
    * @return The maximum length of tuples of this relation, in bytes (equal to
    *         getFixedByteLength() if relation is fixed-length).
    **/
   std::size_t getMaximumByteLength() const {
     return max_byte_length_;
   }

   /**
    * @brief Get the minimum length of tuples of this relation, in bytes.
    *
    * @return The minimum length of tuples of this relation, in bytes (equal
    *         to getFixedByteLength() and getMaximumByteLength() if relation is
    *         fixed-length).
    **/
   std::size_t getMinimumByteLength() const {
     return min_byte_length_;
   }

   /**
    * @brief Get the estimated average length of tuples of this relation, in
    *        bytes.
    *
    * @return The estimated average length of tuples of this relation, in bytes
    *         (equal to getFixedByteLength(), getMinimumByteLength(), and
    *         getMaximumByteLength() if relation is fixed-length).
    **/
   std::size_t getEstimatedByteLength() const {
     return estimated_byte_length_;
   }

   /**
    * @brief Get the total length of the fixed-length attributes in this
    *        relation, in bytes.
    *
    * @return The total length of fixed-length attributes in this relation, in
    *         bytes.
    **/
   std::size_t getFixedByteLength() const {
     return fixed_byte_length_;
   }

   /**
    * @brief Get the total maximum length of the variable-length attributes of
    *        this relation, in bytes.
    *
    * @return The total maximum length of the variable-length attributes of this
    *         relation, in bytes (0 if the relation is fixed-length).
    **/
   std::size_t getMaximumVariableByteLength() const {
     return max_variable_byte_length_;
   }

   /**
    * @brief Get the total minimum length of the variable-length attributes of
    *        this relation, in bytes.
    *
    * @return The total minimum length of the variable-length attributes of this
    *         relation, in bytes (0 if the relation is fixed-length).
    **/
   std::size_t getMinimumVariableByteLength() const {
     return min_variable_byte_length_;
   }

   /**
    * @brief Get the total minimum length of the non-nullable variable-length
    *        attributes of this relation, in bytes.
    *
    * @return The total minimum length of the non-nullable variable-length
    *         attributes of this relation, in bytes (0 if the relation is
    *         fixed-length).
    **/
   std::size_t getMinimumVariableByteLengthExcludingNullable() const {
     return min_variable_byte_length_excluding_nullable_;
   }

   /**
    * @brief Get the estimated average length of all the variable-length
    *        attributes of this relation, in bytes.
    *
    * @return The total estimated average length of variable-length attributes
    *         of this relation, in bytes (0 if the relation is fixed-length).
    **/
   std::size_t getEstimatedVariableByteLength() const {
     return estimated_variable_byte_length_;
   }

   /**
    * @brief Get the byte offset of a fixed-length attribute in this relation.
    * @warning This method should only be called for attributes which are
    *          fixed-length. For debug builds, this is checked with an assert.
    *          For release builds, it is unchecked.
    *
    * @param id The id of the desired attribute.
    * @return The byte-offset of the specified fixed-length attribute (as it
    *         would be in a conventional row-store) in this relation.
    **/
   inline std::size_t getFixedLengthAttributeOffset(const attribute_id id) const {
     DCHECK(hasAttributeWithId(id));
     DCHECK_EQ(-1, variable_length_attribute_indices_[id]);
     return fixed_length_attribute_offsets_[id];
   }

   /**
    * @brief Check whether any attributes of the relation are nullable.
    *
    * @return Whether the relation has any nullable attributes.
    **/
   inline bool hasNullableAttributes() const {
     return num_nullable_attributes_ > 0;
   }

   /**
    * @brief Check how many attributes of the relation are nullable.
    *
    * @return The number of nullable attributes in the relation.
    **/
   inline unsigned numNullableAttributes() const {
     return num_nullable_attributes_;
   }

   /**
    * @brief Get the index of a nullable attribute among all the nullable
    *        attributes in this relation.
    *
    * @param id The id of the desired attribute.
    * @return The attribute's index amongst all of the nullable attributes
    *         (intended for indexing into a NULL bitmap), or -1 if the attribute
    *         is not nullable.
    **/
   inline int getNullableAttributeIndex(const attribute_id id) const {
     DCHECK(hasAttributeWithId(id));
     return nullable_attribute_indices_[id];
   }

   /**
    * @brief Get the number of child attributes.
    *
    * @return The number of child attributes.
    **/
   size_type size() const {
     return attr_map_.size();
   }

   /**
    * @brief Determine whether the sequence of attribute IDs has gaps in it.
    *
    * @return Whether the sequence of attribute IDs has any gaps.
    **/
   bool gapsInAttributeSequence() const {
     return (attr_map_.size() != attr_vec_.size());
   }

   /**
    * @brief Get the highest attribute ID in this relation.
    *
    * @return The highest attribute ID in this relation (-1 if no attributes
    *         exist).
    **/
   attribute_id getMaxAttributeId() const;

   /**
    * @brief Get an iterator at the beginning of the child attributes.
    *
    * @return An iterator on the first child attribute.
    **/
   inline const_iterator begin() const {
     return attr_vec_.begin_skip();
   }

   /**
    * @brief Get an iterator at one-past-the-end of the child attributes.
    *
    * @return An iterator one-past-the-end of the child attributes.
    **/
   inline const_iterator end() const {
     return attr_vec_.end_skip();
   }

   /**
    * @brief Get a vector of the maximum byte lengths for each attribute.
    * @details An index in the vector corresponds with the attribute's id.
    *
    * @return A vector of the maximum byte lengths for each attribute.
    */
   const std::vector<std::size_t>& getMaximumAttributeByteLengths() const {
     return max_byte_lengths_;
   }

  protected:
   /**
    * @brief Create a new relation.
    *
    * @param parent The database this relation belongs to.
    * @param name This relation's name.
    * @param id This relation's ID (defaults to -1, which means invalid/unset).
    * @param temporary Whether this relation is temporary (stores an
    *        intermediate result during query processing).
    **/
   CatalogRelationSchema(CatalogDatabase* parent,
                         const std::string &name,
                         const relation_id id = -1,
                         const bool temporary = false)
       : parent_(parent),
         id_(id),
         name_(name),
         temporary_(temporary),
         num_nullable_attributes_(0),
         num_variable_length_attributes_(0),
         max_byte_length_(0),
         min_byte_length_(0),
         estimated_byte_length_(0),
         fixed_byte_length_(0),
         max_variable_byte_length_(0),
         min_variable_byte_length_(0),
         min_variable_byte_length_excluding_nullable_(0),
         estimated_variable_byte_length_(0),
         current_nullable_attribute_index_(-1),
         current_variable_length_attribute_index_(-1) {
   }

   /**
    * @brief Set the parent CatalogDatabase of this relation. Used by
    *        CatalogDatabase (a friend of this class) when adding a new
    *        relation.
    *
    * @param parent The new parent for this CatalogRelationSchema.
    **/
   void setParent(CatalogDatabase *parent) {
     parent_ = parent;
   }

   /**
    * @brief Set the ID of this relation. Used by CatalogDatabase (a friend of
    *        this class) when adding a new relation.
    *
    * @param id The new ID for this CatalogRelationSchema.
    **/
   void setID(const relation_id id) {
     id_ = id;
   }

   /**
    * @brief Check whether an attribute_id is within the range of IDs contained
    *        in this CatalogRelationSchema.
    *
    * @param id The id to check.
    * @return true if id is in range, false otherwise.
    **/
   bool idInRange(const attribute_id id) const {
     return ((id >= 0)
             && (static_cast<PtrVector<CatalogAttribute>::size_type>(id) < attr_vec_.size()));
   }

   CatalogDatabase *parent_;

   // The relation id in CatalogDatabase.
   relation_id id_;

   // The relation name.
   const std::string name_;

   // Whether a temporary relation.
   const bool temporary_;

   // A vector of attributes, and NULL if it has removed from the relation
   // schema.
   PtrVector<CatalogAttribute, true> attr_vec_;

   // A map from a lower case attribute name to a pointer to the attribute.
   std::unordered_map<std::string, CatalogAttribute*> attr_map_;

   // These schema parameters are cached so we don't have to recalculate them
   // every time.
   unsigned num_nullable_attributes_;
   unsigned num_variable_length_attributes_;
   std::size_t max_byte_length_,
               min_byte_length_,
               estimated_byte_length_,
               fixed_byte_length_,
               max_variable_byte_length_,
               min_variable_byte_length_,
               min_variable_byte_length_excluding_nullable_,
               estimated_variable_byte_length_;
   std::vector<std::size_t> fixed_length_attribute_offsets_;
   std::vector<std::size_t> max_byte_lengths_;

   // Entries are -1 for non-nullable attributes.
   std::vector<int> nullable_attribute_indices_;
   int current_nullable_attribute_index_;

   std::vector<int> variable_length_attribute_indices_;
   int current_variable_length_attribute_index_;

  private:
   friend class CatalogDatabase;

   DISALLOW_COPY_AND_ASSIGN(CatalogRelationSchema);
 };

 /** @} */

 }  // namespace quickstep

 #endif  // QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_
	/**
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	**/

	#ifndef QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_
	#define QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_

	#include <cstddef>
	#include <string>
	#include <unordered_map>
	#include <vector>

	#include "catalog/Catalog.pb.h"
	#include "catalog/CatalogAttribute.hpp"
	#include "catalog/CatalogTypedefs.hpp"
	#include "utility/Macros.hpp"
	#include "utility/PtrVector.hpp"
	#include "utility/StringUtil.hpp"

	#include "glog/logging.h"

	namespace quickstep {

	class CatalogDatabase;

	/** \addtogroup Catalog
	* @{
	*/

	/**
	* @brief A relation in a database. This base class only includes information
	* about the relation's schema. See also CatalogRelation, which augments
	* this with additional information about physical blocks.
	**/
	class CatalogRelationSchema {
	public:
	typedef std::unordered_map<std::string, CatalogAttribute*>::size_type size_type;
	typedef PtrVector<CatalogAttribute, true>::const_skip_iterator const_iterator;

	/**
	* @brief Reconstruct a relation schema from its serialized Protocol Buffer
	* form.
	*
	* @param proto The Protocol Buffer serialization of a relation schema,
	* previously produced by getProto().
	**/
	explicit CatalogRelationSchema(const serialization::CatalogRelationSchema &proto);

	/**
	* @brief Destructor which recursively destroys children.
	**/
	virtual ~CatalogRelationSchema() {}

	/**
	* @brief Serialize the relation schema as Protocol Buffer.
	*
	* @return The Protocol Buffer representation of the relation schema.
	**/
	virtual serialization::CatalogRelationSchema getProto() const;

	/**
	* @brief Check whether a serialization::CatalogRelationSchema is fully-formed
	* and all parts are valid.
	*
	* @param proto A serialized Protocol Buffer representation of a relation
	* schema, originally generated by getProto().
	* @return Whether proto is fully-formed and valid.
	**/
	static bool ProtoIsValid(const serialization::CatalogRelationSchema &proto);

	/**
	* @brief Get the parent database.
	*
	* @return Parent database.
	**/
	const CatalogDatabase& getParent() const {
	return *parent_;
	}

	/**
	* @brief Get a mutable pointer to the parent database.
	*
	* @return Parent database.
	**/
	CatalogDatabase* getParentMutable() {
	return parent_;
	}

	/**
	* @brief Get this relation's ID.
	*
	* @return This relation's ID.
	**/
	relation_id getID() const {
	return id_;
	}

	/**
	* @brief Get this relation's name.
	*
	* @return This relation's name.
	**/
	const std::string& getName() const {
	return name_;
	}

	/**
	* @brief Check whether this relation is temporary or permanent.
	*
	* @return True if this relation is temporary, false otherwise.
	**/
	bool isTemporary() const {
	return temporary_;
	}

	/**
	* @brief Check whether an attribute with the given name exists.
	*
	* @param attr_name The name to check for.
	* @return Whether the attribute exists.
	**/
	bool hasAttributeWithName(const std::string &attr_name) const {
	return (attr_map_.find(ToLower(attr_name)) != attr_map_.end());
	}

	/**
	* @brief Check whether an attribute with the given id exists.
	*
	* @param id The id to check for.
	* @return Whether the attribute exists.
	**/
	bool hasAttributeWithId(const attribute_id id) const {
	return (idInRange(id) && !attr_vec_.elementIsNull(id));
	}

	/**
	* @brief Get an attribute by name. The search is case-insensitive.
	*
	* @param attr_name The name to search for.
	* @return The attribute with the given name. NULL if the attribute is not found.
	**/
	const CatalogAttribute* getAttributeByName(const std::string &attr_name) const;

	/**
	* @brief Get a mutable pointer to an attribute by name. The search is case-insensitive.
	*
	* @param attr_name The name to search for.
	* @return The attribute with the given name. NULL if the attribute is not found.
	**/
	CatalogAttribute* getAttributeByNameMutable(const std::string &attr_name);

	/**
	* @brief Get an attribute by ID.
	*
	* @param id The id to search for.
	* @return The attribute with the given ID.
	**/
	const CatalogAttribute* getAttributeById(const attribute_id id) const {
	if (hasAttributeWithId(id)) {
	return &attr_vec_[id];
	} else {
	return nullptr;
	}
	}

	/**
	* @brief Get a mutable pointer to an attribute by ID.
	*
	* @param id The id to search for.
	* @return The attribute with the given ID.
	* @exception AttributeIdNotFound No attribute with the given ID exists.
	**/
	CatalogAttribute* getAttributeByIdMutable(const attribute_id id) {
	if (hasAttributeWithId(id)) {
	return &(attr_vec_[id]);
	} else {
	return nullptr;
	}
	}

	/**
	* @brief Add a new attribute to the relation. If the attribute already has
	* an ID and/or parent, it will be overwritten.
	*
	* @param new_attr The attribute to be added.
	* @return The id assigned to the attribute.
	* @exception AttributeNameCollision An attribute with the same name as
	* new_attr is already present in the relation.
	**/
	attribute_id addAttribute(CatalogAttribute *new_attr);

	/**
	* @brief Check whether tuples of the relation are variable-length.
	*
	* @return Whether the relation is variable length (i.e. whether any child
	* attributes are variable length).
	**/
	bool isVariableLength() const {
	return num_variable_length_attributes_ > 0;
	}

	/**
	* @brief Check how many attributes of the relation are variable-length.
	*
	* @return The number of variable-length attributes in the relation.
	**/
	inline unsigned numVariableLengthAttributes() const {
	return num_variable_length_attributes_;
	}

	/**
	* @brief Get the index of a variable-length attribute among all the
	* variable-length attributes in this relation.
	*
	* @param id The id of the desired attribute.
	* @return The attribute's index amongst all of the variable-length
	* attributes, or -1 if the attribute is fixed-length.
	**/
	inline int getVariableLengthAttributeIndex(const attribute_id id) const {
	DCHECK(hasAttributeWithId(id));
	return variable_length_attribute_indices_[id];
	}

	/**
	* @brief Get the maximum length of tuples of this relation, in bytes.
	*
	* @return The maximum length of tuples of this relation, in bytes (equal to
	* getFixedByteLength() if relation is fixed-length).
	**/
	std::size_t getMaximumByteLength() const {
	return max_byte_length_;
	}

	/**
	* @brief Get the minimum length of tuples of this relation, in bytes.
	*
	* @return The minimum length of tuples of this relation, in bytes (equal
	* to getFixedByteLength() and getMaximumByteLength() if relation is
	* fixed-length).
	**/
	std::size_t getMinimumByteLength() const {
	return min_byte_length_;
	}

	/**
	* @brief Get the estimated average length of tuples of this relation, in
	* bytes.
	*
	* @return The estimated average length of tuples of this relation, in bytes
	* (equal to getFixedByteLength(), getMinimumByteLength(), and
	* getMaximumByteLength() if relation is fixed-length).
	**/
	std::size_t getEstimatedByteLength() const {
	return estimated_byte_length_;
	}

	/**
	* @brief Get the total length of the fixed-length attributes in this
	* relation, in bytes.
	*
	* @return The total length of fixed-length attributes in this relation, in
	* bytes.
	**/
	std::size_t getFixedByteLength() const {
	return fixed_byte_length_;
	}

	/**
	* @brief Get the total maximum length of the variable-length attributes of
	* this relation, in bytes.
	*
	* @return The total maximum length of the variable-length attributes of this
	* relation, in bytes (0 if the relation is fixed-length).
	**/
	std::size_t getMaximumVariableByteLength() const {
	return max_variable_byte_length_;
	}

	/**
	* @brief Get the total minimum length of the variable-length attributes of
	* this relation, in bytes.
	*
	* @return The total minimum length of the variable-length attributes of this
	* relation, in bytes (0 if the relation is fixed-length).
	**/
	std::size_t getMinimumVariableByteLength() const {
	return min_variable_byte_length_;
	}

	/**
	* @brief Get the total minimum length of the non-nullable variable-length
	* attributes of this relation, in bytes.
	*
	* @return The total minimum length of the non-nullable variable-length
	* attributes of this relation, in bytes (0 if the relation is
	* fixed-length).
	**/
	std::size_t getMinimumVariableByteLengthExcludingNullable() const {
	return min_variable_byte_length_excluding_nullable_;
	}

	/**
	* @brief Get the estimated average length of all the variable-length
	* attributes of this relation, in bytes.
	*
	* @return The total estimated average length of variable-length attributes
	* of this relation, in bytes (0 if the relation is fixed-length).
	**/
	std::size_t getEstimatedVariableByteLength() const {
	return estimated_variable_byte_length_;
	}

	/**
	* @brief Get the byte offset of a fixed-length attribute in this relation.
	* @warning This method should only be called for attributes which are
	* fixed-length. For debug builds, this is checked with an assert.
	* For release builds, it is unchecked.
	*
	* @param id The id of the desired attribute.
	* @return The byte-offset of the specified fixed-length attribute (as it
	* would be in a conventional row-store) in this relation.
	**/
	inline std::size_t getFixedLengthAttributeOffset(const attribute_id id) const {
	DCHECK(hasAttributeWithId(id));
	DCHECK_EQ(-1, variable_length_attribute_indices_[id]);
	return fixed_length_attribute_offsets_[id];
	}

	/**
	* @brief Check whether any attributes of the relation are nullable.
	*
	* @return Whether the relation has any nullable attributes.
	**/
	inline bool hasNullableAttributes() const {
	return num_nullable_attributes_ > 0;
	}

	/**
	* @brief Check how many attributes of the relation are nullable.
	*
	* @return The number of nullable attributes in the relation.
	**/
	inline unsigned numNullableAttributes() const {
	return num_nullable_attributes_;
	}

	/**
	* @brief Get the index of a nullable attribute among all the nullable
	* attributes in this relation.
	*
	* @param id The id of the desired attribute.
	* @return The attribute's index amongst all of the nullable attributes
	* (intended for indexing into a NULL bitmap), or -1 if the attribute
	* is not nullable.
	**/
	inline int getNullableAttributeIndex(const attribute_id id) const {
	DCHECK(hasAttributeWithId(id));
	return nullable_attribute_indices_[id];
	}

	/**
	* @brief Get the number of child attributes.
	*
	* @return The number of child attributes.
	**/
	size_type size() const {
	return attr_map_.size();
	}

	/**
	* @brief Determine whether the sequence of attribute IDs has gaps in it.
	*
	* @return Whether the sequence of attribute IDs has any gaps.
	**/
	bool gapsInAttributeSequence() const {
	return (attr_map_.size() != attr_vec_.size());
	}

	/**
	* @brief Get the highest attribute ID in this relation.
	*
	* @return The highest attribute ID in this relation (-1 if no attributes
	* exist).
	**/
	attribute_id getMaxAttributeId() const;

	/**
	* @brief Get an iterator at the beginning of the child attributes.
	*
	* @return An iterator on the first child attribute.
	**/
	inline const_iterator begin() const {
	return attr_vec_.begin_skip();
	}

	/**
	* @brief Get an iterator at one-past-the-end of the child attributes.
	*
	* @return An iterator one-past-the-end of the child attributes.
	**/
	inline const_iterator end() const {
	return attr_vec_.end_skip();
	}

	/**
	* @brief Get a vector of the maximum byte lengths for each attribute.
	* @details An index in the vector corresponds with the attribute's id.
	*
	* @return A vector of the maximum byte lengths for each attribute.
	*/
	const std::vector<std::size_t>& getMaximumAttributeByteLengths() const {
	return max_byte_lengths_;
	}

	protected:
	/**
	* @brief Create a new relation.
	*
	* @param parent The database this relation belongs to.
	* @param name This relation's name.
	* @param id This relation's ID (defaults to -1, which means invalid/unset).
	* @param temporary Whether this relation is temporary (stores an
	* intermediate result during query processing).
	**/
	CatalogRelationSchema(CatalogDatabase* parent,
	const std::string &name,
	const relation_id id = -1,
	const bool temporary = false)
	: parent_(parent),
	id_(id),
	name_(name),
	temporary_(temporary),
	num_nullable_attributes_(0),
	num_variable_length_attributes_(0),
	max_byte_length_(0),
	min_byte_length_(0),
	estimated_byte_length_(0),
	fixed_byte_length_(0),
	max_variable_byte_length_(0),
	min_variable_byte_length_(0),
	min_variable_byte_length_excluding_nullable_(0),
	estimated_variable_byte_length_(0),
	current_nullable_attribute_index_(-1),
	current_variable_length_attribute_index_(-1) {
	}

	/**
	* @brief Set the parent CatalogDatabase of this relation. Used by
	* CatalogDatabase (a friend of this class) when adding a new
	* relation.
	*
	* @param parent The new parent for this CatalogRelationSchema.
	**/
	void setParent(CatalogDatabase *parent) {
	parent_ = parent;
	}

	/**
	* @brief Set the ID of this relation. Used by CatalogDatabase (a friend of
	* this class) when adding a new relation.
	*
	* @param id The new ID for this CatalogRelationSchema.
	**/
	void setID(const relation_id id) {
	id_ = id;
	}

	/**
	* @brief Check whether an attribute_id is within the range of IDs contained
	* in this CatalogRelationSchema.
	*
	* @param id The id to check.
	* @return true if id is in range, false otherwise.
	**/
	bool idInRange(const attribute_id id) const {
	return ((id >= 0)
	&& (static_cast<PtrVector<CatalogAttribute>::size_type>(id) < attr_vec_.size()));
	}

	CatalogDatabase *parent_;

	// The relation id in CatalogDatabase.
	relation_id id_;

	// The relation name.
	const std::string name_;

	// Whether a temporary relation.
	const bool temporary_;

	// A vector of attributes, and NULL if it has removed from the relation
	// schema.
	PtrVector<CatalogAttribute, true> attr_vec_;

	// A map from a lower case attribute name to a pointer to the attribute.
	std::unordered_map<std::string, CatalogAttribute*> attr_map_;

	// These schema parameters are cached so we don't have to recalculate them
	// every time.
	unsigned num_nullable_attributes_;
	unsigned num_variable_length_attributes_;
	std::size_t max_byte_length_,
	min_byte_length_,
	estimated_byte_length_,
	fixed_byte_length_,
	max_variable_byte_length_,
	min_variable_byte_length_,
	min_variable_byte_length_excluding_nullable_,
	estimated_variable_byte_length_;
	std::vector<std::size_t> fixed_length_attribute_offsets_;
	std::vector<std::size_t> max_byte_lengths_;

	// Entries are -1 for non-nullable attributes.
	std::vector<int> nullable_attribute_indices_;
	int current_nullable_attribute_index_;

	std::vector<int> variable_length_attribute_indices_;
	int current_variable_length_attribute_index_;

	private:
	friend class CatalogDatabase;

	DISALLOW_COPY_AND_ASSIGN(CatalogRelationSchema);
	};

	/** @} */

	} // namespace quickstep

	#endif // QUICKSTEP_CATALOG_CATALOG_RELATION_SCHEMA_HPP_