Add: removing data from DB

src/db.cpp

@@ -208,6 +208,13 @@ ITable::ITable(sqlite3* database, const std::string& name, const std::string& ke
 		throw FileNotGoodException("Cannot prepare write statement");
 	}
 	
+	q = "DELETE FROM `"+name+"` WHERE `"+id_name+"` = ?";
+	d = sqlite3_prepare_v2(m_database,q.c_str(), -1, &m_remove, NULL);
+	if(d != SQLITE_OK) {
+		//infostream<<"WARNING: Database list statment failed to prepare: "<<sqlite3_errmsg(m_database)<<std::endl;
+		throw FileNotGoodException("Cannot prepare remove statement");
+	}
+
 	q = "SELECT `"+id_name+"` FROM `"+name+"`";
 	d = sqlite3_prepare_v2(m_database,q.c_str(), -1, &m_list, NULL);
 	if(d != SQLITE_OK) {
@@ -221,6 +228,8 @@ ITable::~ITable() {
 		sqlite3_finalize(m_read);
 	if(m_write)
 		sqlite3_finalize(m_write);
+	if(m_remove)
+		sqlite3_finalize(m_remove);
 	if(m_list)
 		sqlite3_finalize(m_list);
 }

src/db.h

@@ -190,6 +190,17 @@ public:
 		return d;
 	}
 
+	//deletes row with given key
+	//if failed, returns false
+	template<class Key>
+	bool remove(const Key& key)
+	{
+		DBKeyTypeTraits<Key>::bind(m_remove,1,key);
+		int d = sqlite3_step(m_remove);
+		sqlite3_reset(m_remove);
+		return d == SQLITE_DONE;
+	}
+
 	//inserts all ids from tabale to given list
 	template<class Key>
 	bool getKeys(core::list<Key>& list)
@@ -212,6 +223,7 @@ protected:
 	sqlite3* m_database;
 	sqlite3_stmt *m_read;
 	sqlite3_stmt *m_write;
+	sqlite3_stmt *m_remove;
 	sqlite3_stmt *m_list;
 
 	bool exec(const std::string& query);
@@ -248,6 +260,13 @@ public:
 		return ITable::get<Data>(key);
 	}
 
+	//deletes row with given key
+	//if failed, returns false
+	inline bool remove(const Key& key)
+	{
+		return ITable::remove(key);
+	}
+
 	//inserts all ids from tabale to given list
 	bool getKeys(core::list<Key>& list)
 	{
@@ -291,6 +310,13 @@ public:
 		return ITable::get<Data>(key);
 	}
 
+	//deletes row with given key
+	//if failed, returns false
+	inline bool remove(const Key& key)
+	{
+		return ITable::remove(key);
+	}
+
 	//inserts all ids from tabale to given list
 	bool getKeys(core::list<Key>& list)
 	{

src/scriptapi.cpp

@@ -3746,12 +3746,16 @@ struct Databases {
 		return get_table(table).get<Data>(key);
 	}
 
-	//sets map meta data
 	template<class Data, class Key> bool set_data(int table, const Key& key, const Data& val)
 	{
 		return get_table(table).put(key,val);
 	}
 
+	template<class Key> bool remove_data(int table, const Key& key)
+	{
+		return get_table(table).remove(key);
+	}
+
 } databases;
 
 // get_database(name) -> nil/int
@@ -3876,6 +3880,29 @@ int l_set_table_data(lua_State *L)
 	return luaL_error(L,"set_table_data - error occured");
 }
 
+// remove_table_data(int table, string key_type, key)
+int l_remove_table_data(lua_State *L)
+{
+	try{
+
+		const int table_i = luaL_checkint(L, 1);
+		const std::string key_type = luaL_checkstring(L, 2);
+		const std::string key = param_to_binary(L, 3, key_type);
+
+		/*std::cout << "Tabela: " << table_i
+			<< ", klucz: " << key_type << ":" << key
+			<< ", typ danych: " << data_type << std::endl;*/
+
+		databases.remove_data(table_i,key);
+
+		return 0;
+
+	}catch(std::exception&){}
+
+	//we shall not be here if no error
+	return luaL_error(L,"remove_table_data - error occured");
+}
+
 // get_inventory(location)
 static int l_get_inventory(lua_State *L)
 {
@@ -3964,6 +3991,7 @@ static const struct luaL_Reg minetest_f [] = {
 	{"get_db_table", l_get_db_table},
 	{"get_table_data", l_get_table_data},
 	{"set_table_data", l_set_table_data},
+	{"remove_table_data", l_remove_table_data},
 	{"get_inventory", l_get_inventory},
 	{"get_digging_properties", l_get_digging_properties},
 	{"get_hitting_properties", l_get_hitting_properties},