mirror of
https://github.com/cuberite/SQLiteCpp.git
synced 2025-08-05 02:06:02 -04:00
d36c39ccf3
- Convert last old-style cast to reinterpret_cast<> - Statement::Ptr is now private, with a friend declaration for Column - noexcept should not be defined as the depreacted throw()
500 lines
20 KiB
C++
500 lines
20 KiB
C++
/**
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* @file Statement.h
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* @ingroup SQLiteCpp
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* @brief A prepared SQLite Statement is a compiled SQL query ready to be executed, pointing to a row of result.
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*
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* Copyright (c) 2012-2015 Sebastien Rombauts (sebastien.rombauts@gmail.com)
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*
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* Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt
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* or copy at http://opensource.org/licenses/MIT)
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*/
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#pragma once
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#include <sqlite3.h>
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#include <string>
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#include <map>
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#include <SQLiteCpp/Exception.h>
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namespace SQLite
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{
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// Forward declaration
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class Database;
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class Column;
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/**
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* @brief RAII encapsulation of a prepared SQLite Statement.
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*
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* A Statement is a compiled SQL query ready to be executed step by step
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* to provide results one row at a time.
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*
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* Resource Acquisition Is Initialization (RAII) means that the Statement
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* is compiled in the constructor and finalized in the destructor, so that there is
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* no need to worry about memory management or the validity of the underlying SQLite Statement.
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*
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* Thread-safety: a Statement object shall not be shared by multiple threads, because :
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* 1) in the SQLite "Thread Safe" mode, "SQLite can be safely used by multiple threads
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* provided that no single database connection is used simultaneously in two or more threads."
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* 2) the SQLite "Serialized" mode is not supported by SQLiteC++,
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* because of the way it shares the underling SQLite precompiled statement
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* in a custom shared pointer (See the inner class "Statement::Ptr").
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*/
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class Statement
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{
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friend class Column; // For access to Statement::Ptr inner class
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public:
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/**
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* @brief Compile and register the SQL query for the provided SQLite Database Connection
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*
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* @param[in] aDatabase the SQLite Database Connection
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* @param[in] apQuery an UTF-8 encoded query string
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*
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* Exception is thrown in case of error, then the Statement object is NOT constructed.
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*/
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Statement(Database& aDatabase, const char* apQuery);
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/**
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* @brief Compile and register the SQL query for the provided SQLite Database Connection
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*
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* @param[in] aDatabase the SQLite Database Connection
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* @param[in] aQuery an UTF-8 encoded query string
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*
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* Exception is thrown in case of error, then the Statement object is NOT constructed.
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*/
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Statement(Database& aDatabase, const std::string& aQuery);
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/**
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* @brief Finalize and unregister the SQL query from the SQLite Database Connection.
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*/
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virtual ~Statement() noexcept; // nothrow
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/**
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* @brief Reset the statement to make it ready for a new execution.
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*/
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void reset();
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/**
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* @brief Clears away all the bindings of a prepared statement.
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*
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* Contrary to the intuition of many, reset() does not reset
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* the bindings on a prepared statement.
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* Use this routine to reset all parameters to NULL.
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*/
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void clearBindings(); // throw(SQLite::Exception)
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////////////////////////////////////////////////////////////////////////////
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// Bind a value to a parameter of the SQL statement,
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// in the form "?" (unnamed), "?NNN", ":VVV", "@VVV" or "$VVV".
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//
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// Can use the parameter index, starting from "1", to the higher NNN value,
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// or the complete parameter name "?NNN", ":VVV", "@VVV" or "$VVV"
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// (prefixed with the corresponding sign "?", ":", "@" or "$")
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//
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// Note that for text and blob values, the SQLITE_TRANSIENT flag is used,
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// which tell the sqlite library to make its own copy of the data before the bind() call returns.
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// This choice is done to prevent any common misuses, like passing a pointer to a
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// dynamic allocated and temporary variable (a std::string for instance).
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// This is under-optimized for static data (a static text define in code)
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// as well as for dynamic allocated buffer which could be transfer to sqlite
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// instead of being copied.
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/**
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* @brief Bind an int value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const int aIndex, const int& aValue);
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/**
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* @brief Bind a 64bits int value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const int aIndex, const sqlite3_int64& aValue);
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/**
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* @brief Bind a double (64bits float) value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const int aIndex, const double& aValue);
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/**
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* @brief Bind a string value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const int aIndex, const std::string& aValue);
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/**
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* @brief Bind a text value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const int aIndex, const char* apValue);
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/**
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* @brief Bind a binary blob value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const int aIndex, const void* apValue, const int aSize);
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/**
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* @brief Bind a NULL value to a parameter "?", "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const int aIndex);
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/**
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* @brief Bind an int value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const char* apName, const int& aValue);
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/**
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* @brief Bind a 64bits int value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const char* apName, const sqlite3_int64& aValue);
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/**
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* @brief Bind a double (64bits float) value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const char* apName, const double& aValue);
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/**
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* @brief Bind a string value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const char* apName, const std::string& aValue);
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/**
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* @brief Bind a text value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const char* apName, const char* apValue);
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/**
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* @brief Bind a binary blob value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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void bind(const char* apName, const void* apValue, const int aSize);
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/**
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* @brief Bind a NULL value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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void bind(const char* apName); // bind NULL value
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/**
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* @brief Bind an int value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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inline void bind(const std::string& aName, const int& aValue)
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{
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bind(aName.c_str(), aValue);
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}
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/**
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* @brief Bind a 64bits int value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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inline void bind(const std::string& aName, const sqlite3_int64& aValue)
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{
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bind(aName.c_str(), aValue);
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}
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/**
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* @brief Bind a double (64bits float) value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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inline void bind(const std::string& aName, const double& aValue)
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{
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bind(aName.c_str(), aValue);
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}
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/**
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* @brief Bind a string value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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inline void bind(const std::string& aName, const std::string& aValue)
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{
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bind(aName.c_str(), aValue);
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}
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/**
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* @brief Bind a text value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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inline void bind(const std::string& aName, const char* apValue)
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{
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bind(aName.c_str(), apValue);
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}
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/**
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* @brief Bind a binary blob value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*
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* @note This uses the SQLITE_TRANSIENT flag, making a copy of the data, for SQLite internal use
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*/
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inline void bind(const std::string& aName, const void* apValue, const int aSize)
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{
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bind(aName.c_str(), apValue, aSize);
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}
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/**
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* @brief Bind a NULL value to a named parameter "?NNN", ":VVV", "@VVV" or "$VVV" in the SQL prepared statement (aIndex >= 1)
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*/
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inline void bind(const std::string& aName) // bind NULL value
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{
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bind(aName.c_str());
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}
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////////////////////////////////////////////////////////////////////////////
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/**
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* @brief Execute a step of the prepared query to fetch one row of results.
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*
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* While true is returned, a row of results is available, and can be accessed
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* thru the getColumn() method
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*
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* @see exec() execute a one-step prepared statement with no expected result
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* @see Database::exec() is a shortcut to execute one or multiple statements without results
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*
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* @return - true (SQLITE_ROW) if there is another row ready : you can call getColumn(N) to get it
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* then you have to call executeStep() again to fetch more rows until the query is finished
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* - false (SQLITE_DONE) if the query has finished executing : there is no (more) row of result
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* (case of a query with no result, or after N rows fetched successfully)
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*
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* @throw SQLite::Exception in case of error
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*/
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bool executeStep();
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/**
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* @brief Execute a one-step query with no expected result.
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*
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* This method is useful for any kind of statements other than the Data Query Language (DQL) "SELECT" :
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* - Data Definition Language (DDL) statements "CREATE", "ALTER" and "DROP"
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* - Data Manipulation Language (DML) statements "INSERT", "UPDATE" and "DELETE"
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* - Data Control Language (DCL) statements "GRANT", "REVOKE", "COMMIT" and "ROLLBACK"
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*
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* It is similar to Database::exec(), but using a precompiled statement, it adds :
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* - the ability to bind() arguments to it (best way to insert data),
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* - reusing it allows for better performances (efficient for multiple insertion).
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*
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* @see executeStep() execute a step of the prepared query to fetch one row of results
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* @see Database::exec() is a shortcut to execute one or multiple statements without results
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*
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* @return number of row modified by this SQL statement (INSERT, UPDATE or DELETE)
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*
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* @throw SQLite::Exception in case of error, or if row of results are returned !
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*/
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int exec();
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////////////////////////////////////////////////////////////////////////////
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/**
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* @brief Return a copy of the column data specified by its index
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*
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* Can be used to access the data of the current row of result when applicable,
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* while the executeStep() method returns true.
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*
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* Throw an exception if there is no row to return a Column from:
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* - if provided index is out of bound
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* - before any executeStep() call
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* - after the last executeStep() returned false
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* - after a reset() call
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*
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* Throw an exception if the specified index is out of the [0, getColumnCount()) range.
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*
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* @param[in] aIndex Index of the column, starting at 0
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*
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* @note This method is not const, reflecting the fact that the returned Column object will
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* share the ownership of the underlying sqlite3_stmt.
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*
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* @warning The resulting Column object must not be memorized "as-is".
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* Is is only a wrapper around the current result row, so it is only valid
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* while the row from the Statement remains valid, that is only until next executeStep() call.
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* Thus, you should instead extract immediately its data (getInt(), getText()...)
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* and use or copy this data for any later usage.
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*/
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Column getColumn(const int aIndex);
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/**
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* @brief Return a copy of the column data specified by its column name (less efficient than using an index)
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*
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* Can be used to access the data of the current row of result when applicable,
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* while the executeStep() method returns true.
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*
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* Throw an exception if there is no row to return a Column from :
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* - if provided name is not one of the aliased column names
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* - before any executeStep() call
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* - after the last executeStep() returned false
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* - after a reset() call
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*
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* Throw an exception if the specified name is not an on of the aliased name of the columns in the result.
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*
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* @param[in] apName Aliased name of the column, that is, the named specified in the query (not the original name)
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*
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* @note Uses a map of column names to indexes, build on first call.
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*
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* @note This method is not const, reflecting the fact that the returned Column object will
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* share the ownership of the underlying sqlite3_stmt.
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*
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* @warning The resulting Column object must not be memorized "as-is".
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* Is is only a wrapper around the current result row, so it is only valid
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* while the row from the Statement remains valid, that is only until next executeStep() call.
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* Thus, you should instead extract immediately its data (getInt(), getText()...)
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* and use or copy this data for any later usage.
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*/
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Column getColumn(const char* apName);
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/**
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* @brief Test if the column value is NULL
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*
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* @param[in] aIndex Index of the column, starting at 0
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*
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* @return true if the column value is NULL
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*
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* Throw an exception if the specified index is out of the [0, getColumnCount()) range.
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*/
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bool isColumnNull(const int aIndex) const;
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/**
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* @brief Return a pointer to the named assigned to the specified result column (potentially aliased)
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*
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* @see getColumnOriginName() to get original column name (not aliased)
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*
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* Throw an exception if the specified index is out of the [0, getColumnCount()) range.
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*/
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const char* getColumnName(const int aIndex) const;
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#ifdef SQLITE_ENABLE_COLUMN_METADATA
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/**
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* @brief Return a pointer to the table column name that is the origin of the specified result column
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*
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* Require definition of the SQLITE_ENABLE_COLUMN_METADATA preprocessor macro :
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* - when building the SQLite library itself (which is the case for the Debian libsqlite3 binary for instance),
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* - and also when compiling this wrapper.
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*
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* Throw an exception if the specified index is out of the [0, getColumnCount()) range.
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*/
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const char* getColumnOriginName(const int aIndex) const;
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#endif
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////////////////////////////////////////////////////////////////////////////
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/// @brief Return the UTF-8 SQL Query.
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inline const std::string& getQuery() const
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{
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return mQuery;
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}
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/// @brief Return the number of columns in the result set returned by the prepared statement
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inline int getColumnCount() const
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{
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return mColumnCount;
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}
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/// @brief true when a row has been fetched with executeStep()
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inline bool isOk() const
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{
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return mbOk;
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}
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/// @brief true when the last executeStep() had no more row to fetch
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inline bool isDone() const
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{
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return mbDone;
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}
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/// @brief Return the numeric result code for the most recent failed API call (if any).
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inline int getErrorCode() const noexcept // nothrow
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{
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return sqlite3_errcode(mStmtPtr);
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}
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/// @brief Return the extended numeric result code for the most recent failed API call (if any).
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inline int getExtendedErrorCode() const noexcept // nothrow
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{
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return sqlite3_extended_errcode(mStmtPtr);
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}
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/// Return UTF-8 encoded English language explanation of the most recent failed API call (if any).
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inline const char* errmsg() const noexcept // nothrow
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{
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return sqlite3_errmsg(mStmtPtr);
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}
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private:
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/**
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* @brief Shared pointer to the sqlite3_stmt SQLite Statement Object.
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*
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* Manage the finalization of the sqlite3_stmt with a reference counter.
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*
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* This is a internal class, not part of the API (hence full documentation is in the cpp).
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*/
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class Ptr
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{
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public:
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// Prepare the statement and initialize its reference counter
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Ptr(sqlite3* apSQLite, std::string& aQuery);
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// Copy constructor increments the ref counter
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Ptr(const Ptr& aPtr);
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// Decrement the ref counter and finalize the sqlite3_stmt when it reaches 0
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~Ptr() noexcept; // nothrow (no virtual destructor needed here)
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/// @brief Inline cast operator returning the pointer to SQLite Database Connection Handle
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inline operator sqlite3*() const
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{
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return mpSQLite;
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}
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/// @brief Inline cast operator returning the pointer to SQLite Statement Object
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inline operator sqlite3_stmt*() const
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{
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return mpStmt;
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}
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private:
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/// @{ Unused/forbidden copy operator
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Ptr& operator=(const Ptr& aPtr);
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/// @}
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private:
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sqlite3* mpSQLite; //!< Pointer to SQLite Database Connection Handle
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sqlite3_stmt* mpStmt; //!< Pointer to SQLite Statement Object
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unsigned int* mpRefCount; //!< Pointer to the heap allocated reference counter of the sqlite3_stmt
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//!< (to share it with Column objects)
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};
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private:
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/// @{ Statement must be non-copyable
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Statement(const Statement&);
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Statement& operator=(const Statement&);
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/// @}
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/**
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* @brief Check if a return code equals SQLITE_OK, else throw a SQLite::Exception with the SQLite error message
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*
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* @param[in] SQLite return code to test against the SQLITE_OK expected value
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*/
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inline void check(const int aRet) const
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{
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if (SQLITE_OK != aRet)
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{
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throw SQLite::Exception(sqlite3_errmsg(mStmtPtr));
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|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Check if there is a row of result returnes by executeStep(), else throw a SQLite::Exception.
|
|
*/
|
|
inline void checkRow() const
|
|
{
|
|
if (false == mbOk)
|
|
{
|
|
throw SQLite::Exception("No row to get a column from. executeStep() was not called, or returned false.");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Check if there is a Column index is in the range of columns in the result.
|
|
*/
|
|
inline void checkIndex(const int aIndex) const
|
|
{
|
|
if ((aIndex < 0) || (aIndex >= mColumnCount))
|
|
{
|
|
throw SQLite::Exception("Column index out of range.");
|
|
}
|
|
}
|
|
|
|
private:
|
|
typedef std::map<std::string, int> TColumnNames;
|
|
|
|
private:
|
|
std::string mQuery; //!< UTF-8 SQL Query
|
|
Ptr mStmtPtr; //!< Shared Pointer to the prepared SQLite Statement Object
|
|
int mColumnCount; //!< Number of columns in the result of the prepared statement
|
|
TColumnNames mColumnNames; //!< Map of columns index by name
|
|
bool mbOk; //!< true when a row has been fetched with executeStep()
|
|
bool mbDone; //!< true when the last executeStep() had no more row to fetch
|
|
};
|
|
|
|
|
|
} // namespace SQLite
|