drop table added

Readme.md

@@ -1,11 +1,10 @@
 
 ### TODO
-- drop table command
+- support for *
-- move csv generation from usql(save_table) to table class
+- support for order by, offset, limit
-- add exceptions and rename it to UsqlException
-- class members should have prefix m_
-- maybe to create iterator on table
 - add pipe | token
 - add count min and max functions, eg aggregate functions
-- add logging
+- maybe to create iterator on table
+- add exceptions and rename it to UsqlException
+- class members should have prefix m_
 - add const wherever should be

lexer.cpp

@@ -162,6 +162,9 @@ namespace usql {
 	    if (token == "create")
 		    return TokenType::keyword_create;
 
+	    if (token == "drop")
+		    return TokenType::keyword_drop;
+
 	    if (token == "where")
 		    return TokenType::keyword_where;
 
@@ -338,6 +341,9 @@ namespace usql {
 		    case TokenType::keyword_create:
 			    txt = "create";
 			    break;
+		    case TokenType::keyword_drop:
+			    txt = "drop";
+			    break;
 		    case TokenType::keyword_where:
 			    txt = "where";
 			    break;

lexer.h

@@ -22,6 +22,7 @@ namespace usql {
 	lesser_equal,
 	keyword_as,
 	keyword_create,
+	keyword_drop,
 	keyword_table,
 	keyword_where,
 	keyword_delete,

main.cpp

@@ -3,15 +3,13 @@
 
 // https://dev.to/joaoh82/what-would-sqlite-look-like-if-written-in-rust-part-1-2np4
 
-// parser should get m_lexer as param and table executor to be able translate * or get types or so
+using namespace std::chrono;
-// podporovat create as select
-// drop table
 
 int main(int argc, char *argv[]) {
 	std::vector<std::string> sql_commands{
 		    "create table a (i integer not null, s varchar(64), f float null)",
 		    "insert into a (i, s) values(1, upper('one'))",
-		    "update table a set s = 'null string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'",
+		    "update table a set s = 'null string aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'",
 //		    "update table a set i = null",
 		    "insert into a (i, s) values(2, 'two')",
 		    "insert into a (i, s) values(3, 'two')",
@@ -36,19 +34,25 @@ int main(int argc, char *argv[]) {
 		    "select i, s, f from a where i < 300",
 		    "create table x as select i, s, f from a where i < 300",
 		    "select i, s, f from x where i < 300",
+		    "drop table x",
 		    "select i, s, f from a where i > 300",
 		    "select i, to_string(i, '%d.%m.%Y'), s, f from a where i > 300",
 		    "create table prices (datetime integer, symbol varchar(8), prev_close float, open float, price float, change float, change_prct varchar(16))",
+		    "load prices from '/Users/vaclavt/Library/Mobile Documents/com~apple~CloudDocs/Development/usql/prices.csv'",
 		    "insert into prices (datetime, symbol, prev_close, open, price, change, change_prct) values (1626979443, 'MPC', 54.08, 53.82, 53.63, -0.832101, '-0.83 %')",
-		    "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct from prices"
+		    "select to_string(datetime, '%d.%m.%Y %H:%M:%S'), symbol, prev_close, open, price, change, change_prct from prices where symbol = 'SYF'"
 	};
 
 
 	usql::USql uSql{};
 
 	for (auto command : sql_commands) {
-		std::cout << command << std::endl;
+		time_point<high_resolution_clock> start_time = high_resolution_clock::now();
 		auto result = uSql.execute(command);
+		time_point<high_resolution_clock> end_time = high_resolution_clock::now();
+
+		std::cout << command << std::endl;
+		std::cout << "run time: " << duration_cast<milliseconds>(end_time - start_time).count() << " ms " << std::endl;
 
 		result->print();
 	}

parser.cpp

@@ -13,27 +13,22 @@ namespace usql {
 	    m_lexer.parse(code);
 	    // m_lexer.debugTokens();
 
-	    if (m_lexer.tokenType() == TokenType::keyword_create && m_lexer.nextTokenType() == TokenType::keyword_table) {
+	    if (m_lexer.tokenType() == TokenType::keyword_create && m_lexer.nextTokenType() == TokenType::keyword_table)
 		    return parse_create_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_insert)
-	    if (m_lexer.tokenType() == TokenType::keyword_insert) {
 		    return parse_insert_into_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_select)
-	    if (m_lexer.tokenType() == TokenType::keyword_select) {
 		    return parse_select_from_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_delete)
-	    if (m_lexer.tokenType() == TokenType::keyword_delete) {
 		    return parse_delete_from_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_update)
-	    if (m_lexer.tokenType() == TokenType::keyword_update) {
 		    return parse_update_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_load)
-	    if (m_lexer.tokenType() == TokenType::keyword_load) {
 		    return parse_load_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_save)
-	    if (m_lexer.tokenType() == TokenType::keyword_save) {
 		    return parse_save_table();
-	    }
+	    if (m_lexer.tokenType() == TokenType::keyword_drop)
+		    return parse_drop_table();
 
 	    std::cout << "ERROR, token:" << m_lexer.currentToken().token_string << std::endl;
 	    return std::make_unique<Node>(NodeType::error);
@@ -110,7 +105,41 @@ namespace usql {
 	    }
     }
 
+    std::unique_ptr<Node> Parser::parse_load_table() {
+	    m_lexer.skipToken(TokenType::keyword_load);
+	    m_lexer.skipTokenOptional(TokenType::keyword_into);
 
+	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
+
+	    m_lexer.skipTokenOptional(TokenType::keyword_from);
+
+	    std::string file_name = m_lexer.consumeCurrentToken().token_string;
+
+	    return std::make_unique<LoadIntoTableNode>(table_name, file_name);
+    }
+
+    std::unique_ptr<Node> Parser::parse_save_table() {
+    	m_lexer.skipToken(TokenType::keyword_save);
+    	m_lexer.skipTokenOptional(TokenType::keyword_table);
+
+    	std::string table_name = m_lexer.consumeCurrentToken().token_string;
+
+    	m_lexer.skipTokenOptional(TokenType::keyword_into);
+
+    	std::string file_name = m_lexer.consumeCurrentToken().token_string;
+
+    	return std::make_unique<SaveTableNode>(table_name, file_name);
+    }
+
+    std::unique_ptr<Node> Parser::parse_drop_table() {
+    	m_lexer.skipToken(TokenType::keyword_drop);
+    	m_lexer.skipTokenOptional(TokenType::keyword_table);
+
+    	std::string table_name = m_lexer.consumeCurrentToken().token_string;
+
+    	return std::make_unique<DropTableNode>(table_name);
+    }
+ 
     std::unique_ptr<Node> Parser::parse_insert_into_table() {
 	    std::vector<ColNameNode> column_names{};
 	    std::vector<std::unique_ptr<Node>> column_values{};
@@ -261,33 +290,6 @@ std::unique_ptr<Node> Parser::parse_select_from_table() {
 	    return std::make_unique<UpdateTableNode>(table_name, cols_names, std::move(values), std::move(where_node));
     }
 
-    std::unique_ptr<Node> Parser::parse_load_table() {
-	    m_lexer.skipToken(TokenType::keyword_load);
-	    m_lexer.skipTokenOptional(TokenType::keyword_into);
-
-	    std::string table_name = m_lexer.consumeCurrentToken().token_string;
-
-	    m_lexer.skipTokenOptional(TokenType::keyword_from);
-
-	    std::string file_name = m_lexer.consumeCurrentToken().token_string;
-
-	    return std::make_unique<LoadIntoTableNode>(table_name, file_name);
-    }
-
-
-    std::unique_ptr<Node> Parser::parse_save_table() {
-    	m_lexer.skipToken(TokenType::keyword_save);
-    	m_lexer.skipTokenOptional(TokenType::keyword_table);
-
-    	std::string table_name = m_lexer.consumeCurrentToken().token_string;
-
-    	m_lexer.skipTokenOptional(TokenType::keyword_into);
-
-    	std::string file_name = m_lexer.consumeCurrentToken().token_string;
-
-    	return std::make_unique<SaveTableNode>(table_name, file_name);
-    }
-
     std::unique_ptr<Node> Parser::parse_where_clause() {
 	    // TODO add support for multiple filters
 	    // TODO add support for parenthesis

parser.h

@@ -32,6 +32,7 @@ namespace usql {
 	update_table,
 	load_table,
 	save_table,
+	drop_table,
 	column_name,
 	column_value,
 	function,
@@ -256,6 +257,12 @@ namespace usql {
         Node(NodeType::save_table), table_name(name), filename(file) {}
     };
 
+    struct DropTableNode : Node {
+        std::string table_name;
+
+        DropTableNode(const std::string& name) : Node(NodeType::drop_table), table_name(name) {}
+    };
+
     struct DeleteFromTableNode : Node {
 	std::string table_name;
 	std::unique_ptr<Node> where;
@@ -275,15 +282,18 @@ namespace usql {
 
     private:
 	std::unique_ptr<Node> parse_create_table();
+	std::unique_ptr<Node> parse_load_table();
+	std::unique_ptr<Node> parse_save_table();
+	std::unique_ptr<Node> parse_drop_table();
+
 	std::unique_ptr<Node> parse_insert_into_table();
-	std::unique_ptr<Node> parse_value();
 	std::unique_ptr<Node> parse_select_from_table();
 	std::unique_ptr<Node> parse_delete_from_table();
 	std::unique_ptr<Node> parse_update_table();
-	std::unique_ptr<Node> parse_load_table();
+
-	std::unique_ptr<Node> parse_save_table();
 	std::unique_ptr<Node> parse_where_clause();
 	std::unique_ptr<Node> parse_operand_node();
+	std::unique_ptr<Node> parse_value();
 	RelationalOperatorType parse_relational_operator();
 	LogicalOperatorType parse_logical_operator();
 	ArithmeticalOperatorType parse_arithmetical_operator();

table.cpp

@@ -1,5 +1,7 @@
 
 #include "table.h"
+#include "csvreader.h"
+
 
 namespace usql {
 
@@ -49,6 +51,43 @@ std::string Table::csv_string() {
 	return out_string;
 }
 
+int Table::load_csv_string(const std::string &content) {
+	int row_cnt = 0;
+
+	CsvReader csvparser{};
+	auto csv = csvparser.parseCSV(content);
+
+	std::vector<ColDefNode> &colDefs = m_col_defs;
+
+	for (auto it = csv.begin() + 1; it != csv.end(); ++it) {
+		std::vector<std::string> csv_line = *it;
+
+		// prepare empty new_row
+		Row new_row = create_empty_row();
+
+		// copy values
+		for (size_t i = 0; i < columns_count(); i++) {
+			ColDefNode col_def = get_column_def(colDefs[i].name);
+
+			// TODO validate value
+			if (col_def.type == ColumnType::integer_type) {
+				new_row.setColumnValue(col_def.order, std::stol(csv_line[i]));
+			} else if (col_def.type == ColumnType::float_type) {
+				new_row.setColumnValue(col_def.order, std::stof(csv_line[i]));
+			} else {
+				new_row.setColumnValue(col_def.order, csv_line[i]);
+			}
+		}
+
+		// append new_row
+		add_row(new_row);
+
+		row_cnt++;
+	}
+
+	return row_cnt;
+}
+
 void Table::print() {
 	std::cout << "** " << m_name << " **" << std::endl;
 	for (auto row : m_rows) {

table.h

@@ -26,6 +26,7 @@ namespace usql {
 	void validate_row(const Row &row);
 
 	std::string csv_string();
+	int load_csv_string(const std::string &content);
 
 	void print();
 

usql.cpp

@@ -1,6 +1,5 @@
 #include "usql.h"
 #include "exception.h"
-#include "csvreader.h"
 #include "ml_date.h"
 
 #include <algorithm>
@@ -14,7 +13,7 @@ std::unique_ptr<Table> USql::execute(const std::string &command) {
 		return execute(*node);
 
 	} catch (std::exception &e) {
-		return create_stmt_result_table(-1, e.what());
+		return create_stmt_result_table(-1, e.what(), 0);
 	}
 
 }
@@ -38,8 +37,10 @@ std::unique_ptr<Table> USql::execute(Node &node) {
 			return execute_load(static_cast<LoadIntoTableNode &>(node));
 		case NodeType::save_table:
 			return execute_save(static_cast<SaveTableNode &>(node));
+		case NodeType::drop_table:
+			return execute_drop(static_cast<DropTableNode &>(node));
 		default:
-			return create_stmt_result_table(-1, "unknown statement");
+			return create_stmt_result_table(-1, "unknown statement", 0);
 	}
 }
 
@@ -50,7 +51,7 @@ std::unique_ptr<Table> USql::execute_create_table(CreateTableNode &node) {
 	Table table{node.table_name, node.cols_defs};
 	m_tables.push_back(table);
 
-	return create_stmt_result_table(0, "table created");
+	return create_stmt_result_table(0, "table created", 0);
 }
 
 
@@ -72,10 +73,54 @@ std::unique_ptr<Table> USql::execute_create_table_as_table(CreateTableAsSelectNo
 
 	select.release();	// is it correct? hoping not to release select table here and then when releasing CreateTableAsSelectNode
 
-	return create_stmt_result_table(0, "table created");
+	return create_stmt_result_table(0, "table created", table->m_rows.size());
 }
 
 
+
+std::unique_ptr<Table> USql::execute_load(LoadIntoTableNode &node) {
+	// find source table
+	Table *table_def = find_table(node.table_name);
+
+	// read data
+	std::ifstream ifs(node.filename);
+	std::string content((std::istreambuf_iterator<char>(ifs)),
+			    (std::istreambuf_iterator<char>()));
+
+	// load rows
+	auto rows_cnt = table_def->load_csv_string(content);
+
+	return create_stmt_result_table(0, "load succeeded", rows_cnt);
+}
+
+
+std::unique_ptr<Table> USql::execute_save(SaveTableNode &node) {
+	// find source table
+	Table *table_def = find_table(node.table_name);
+
+	// make csv string
+	std::string csv_string = table_def->csv_string();
+
+	// save data
+	std::ofstream file(node.filename);
+	file << csv_string;
+	file.close();
+
+	return create_stmt_result_table(0, "save succeeded", 0);
+}
+
+std::unique_ptr<Table> USql::execute_drop(DropTableNode &node) {
+	auto name_cmp = [node](const Table& t) { return t.m_name == node.table_name; };
+
+	auto table_def = std::find_if(begin(m_tables), end(m_tables), name_cmp);
+	if (table_def != std::end(m_tables)) {
+		m_tables.erase(table_def);
+		return create_stmt_result_table(0, "drop succeeded", 0);
+	}
+
+	throw Exception("table not found (" + node.table_name + ")");
+}
+
 std::unique_ptr<Table> USql::execute_insert_into_table(InsertIntoTableNode &node) {
 	// TODO check column names.size = values.size
 
@@ -88,7 +133,7 @@ std::unique_ptr<Table> USql::execute_insert_into_table(InsertIntoTableNode &node
 	// copy values
 	for (size_t i = 0; i < node.cols_names.size(); i++) {
 		ColDefNode col_def = table_def->get_column_def(node.cols_names[i].name);
-		auto col_value = evalValueNode(table_def, new_row, node.cols_values[i].get());
+		auto col_value = eval_value_node(table_def, new_row, node.cols_values[i].get());
 
 		new_row.setColumnValue(&col_def, col_value.get());
 	}
@@ -96,7 +141,7 @@ std::unique_ptr<Table> USql::execute_insert_into_table(InsertIntoTableNode &node
 	// append new_row
 	table_def->add_row(new_row);
 
-	return create_stmt_result_table(0, "insert succeeded");
+	return create_stmt_result_table(0, "insert succeeded", 1);
 }
 
 
@@ -122,7 +167,7 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 	// execute access plan
 	for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
 		// eval where for row
-		if (evalWhere(node.where.get(), table, *row)) {
+		if (eval_where(node.where.get(), table, *row)) {
 			// prepare empty row
 			Row new_row = result->create_empty_row();
 
@@ -131,7 +176,8 @@ std::unique_ptr<Table> USql::execute_select(SelectFromTableNode &node) {
 				auto row_col_index = source_table_col_index[idx];
 
 				if (row_col_index == -1) {	// TODO introduce constant here
-					auto evaluated_value = evalValueNode(table, *row, node.cols_names->operator[](idx).value.get());
+					auto evaluated_value = eval_value_node(table, *row, node.cols_names->operator[](
+						    idx).value.get());
 					ValueNode *col_value = evaluated_value.get();
 
 					new_row.setColumnValue(&result_tbl_col_defs[idx], col_value);
@@ -178,16 +224,18 @@ std::unique_ptr<Table> USql::execute_delete(DeleteFromTableNode &node) {
 	Table *table = find_table(node.table_name);
 
 	// execute access plan
+	int affected_rows = 0;
 	auto it = table->m_rows.begin();
 	for (; it != table->m_rows.end();) {
-		if (evalWhere(node.where.get(), table, *it)) {
+		if (eval_where(node.where.get(), table, *it)) {
 			it = table->m_rows.erase(it);
+			affected_rows++;
 		} else {
 			++it;
 		}
 	}
 
-	return create_stmt_result_table(0, "delete succeeded");
+	return create_stmt_result_table(0, "delete succeeded", affected_rows);
 }
 
 
@@ -196,92 +244,38 @@ std::unique_ptr<Table> USql::execute_update(UpdateTableNode &node) {
 	Table *table = find_table(node.table_name);
 
 	// execute access plan
+	int affected_rows = 0;
 	for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
 		// eval where for row
-		if (evalWhere(node.where.get(), table, *row)) {
+		if (eval_where(node.where.get(), table, *row)) {
 			int i = 0;
 			for (const auto& col : node.cols_names) {
 				ColDefNode col_def = table->get_column_def(col.name);	// TODO cache it like in select
-				std::unique_ptr<ValueNode> new_val = evalArithmeticOperator(col_def.type,
+				std::unique_ptr<ValueNode> new_val = eval_arithmetic_operator(col_def.type,
-						      static_cast<ArithmeticalOperatorNode &>(*node.values[i]), table, *row);
+											      static_cast<ArithmeticalOperatorNode &>(*node.values[i]),
+											      table, *row);
 
 				table->validate_column(&col_def, new_val.get());
 				row->setColumnValue(&col_def, new_val.get());
 				i++;
 			}
+			affected_rows++;
 			// TODO tady je problem, ze kdyz to zfajluje na jednom radku ostatni by se nemely provest
 		}
 	}
 
-	return create_stmt_result_table(0, "delete succeeded");
+	return create_stmt_result_table(0, "update succeeded", affected_rows);
 }
 
 
-std::unique_ptr<Table> USql::execute_load(LoadIntoTableNode &node) {
+bool USql::eval_where(Node *where, Table *table, Row &row) const {
-	// find source table
-	Table *table_def = find_table(node.table_name);
-
-	// read data
-	std::ifstream ifs(node.filename);
-	std::string content((std::istreambuf_iterator<char>(ifs)),
-			    (std::istreambuf_iterator<char>()));
-
-	CsvReader csvparser{};
-	auto csv = csvparser.parseCSV(content);
-
-	std::vector<ColDefNode> &colDefs = table_def->m_col_defs;
-
-	for (auto it = csv.begin() + 1; it != csv.end(); ++it) {
-		std::vector<std::string> csv_line = *it;
-
-		// prepare empty new_row
-		Row new_row = table_def->create_empty_row();
-
-		// copy values
-		for (size_t i = 0; i < table_def->columns_count(); i++) {
-			ColDefNode col_def = table_def->get_column_def(colDefs[i].name);
-
-			// TODO validate value
-			if (col_def.type == ColumnType::integer_type) {
-				new_row.setColumnValue(col_def.order, std::stol(csv_line[i]));
-			} else if (col_def.type == ColumnType::float_type) {
-				new_row.setColumnValue(col_def.order, std::stof(csv_line[i]));
-			} else {
-				new_row.setColumnValue(col_def.order, csv_line[i]);
-			}
-		}
-
-		// append new_row
-		table_def->add_row(new_row);
-	}
-
-	return create_stmt_result_table(0, "load succeeded");
-}
-
-
-std::unique_ptr<Table> USql::execute_save(SaveTableNode &node) {
-	// find source table
-	Table *table_def = find_table(node.table_name);
-
-	std::string csv_string = table_def->csv_string();
-
-	// save data
-	std::ofstream file(node.filename);
-	file << csv_string;
-	file.close();
-
-	return create_stmt_result_table(0, "save succeeded");
-}
-
-
-bool USql::evalWhere(Node *where, Table *table, Row &row) const {
 	switch (where->node_type) {    // no where clause
 		case NodeType::true_node:
 			return true;
 		case NodeType::relational_operator:     //  just one condition
-			return evalRelationalOperator(*((RelationalOperatorNode *) where), table, row);
+			return eval_relational_operator(*((RelationalOperatorNode *) where), table, row);
 		case NodeType::logical_operator:
-			return evalLogicalOperator(*((LogicalOperatorNode *) where), table, row);
+			return eval_logical_operator(*((LogicalOperatorNode *) where), table, row);
 		default:
 			throw Exception("Wrong node type");
 	}
@@ -290,9 +284,9 @@ bool USql::evalWhere(Node *where, Table *table, Row &row) const {
 }
 
 
-bool USql::evalRelationalOperator(const RelationalOperatorNode &filter, Table *table, Row &row) const {
+bool USql::eval_relational_operator(const RelationalOperatorNode &filter, Table *table, Row &row) const {
-	std::unique_ptr<ValueNode> left_value = evalValueNode(table, row, filter.left.get());
+	std::unique_ptr<ValueNode> left_value = eval_value_node(table, row, filter.left.get());
-	std::unique_ptr<ValueNode> right_value = evalValueNode(table, row, filter.right.get());
+	std::unique_ptr<ValueNode> right_value = eval_value_node(table, row, filter.right.get());
 
 	double comparator;
 
@@ -327,15 +321,15 @@ bool USql::evalRelationalOperator(const RelationalOperatorNode &filter, Table *t
 }
 
 
-std::unique_ptr<ValueNode> USql::evalValueNode(Table *table, Row &row, Node *node) {
+std::unique_ptr<ValueNode> USql::eval_value_node(Table *table, Row &row, Node *node) {
 	if (node->node_type == NodeType::database_value || node->node_type == NodeType::column_name) {	// TODO sjednotit
-		return evalDatabaseValueNode(table, row, node);
+		return eval_database_value_node(table, row, node);
 
 	} else if (node->node_type == NodeType::int_value || node->node_type == NodeType::float_value || node->node_type == NodeType::string_value) {
-		return evalLiteralValueNode(table, row, node);
+		return eval_literal_value_node(table, row, node);
 
 	} else if (node->node_type == NodeType::function) {
-		return evalFunctionValueNode(table, row, node);
+		return eval_function_value_node(table, row, node);
 	} else if (node->node_type == NodeType::null_value) {
 		return std::make_unique<NullValueNode>();
 	}
@@ -343,7 +337,7 @@ std::unique_ptr<ValueNode> USql::evalValueNode(Table *table, Row &row, Node *nod
 }
 
 
-std::unique_ptr<ValueNode> USql::evalDatabaseValueNode(Table *table, Row &row, Node *node) {
+std::unique_ptr<ValueNode> USql::eval_database_value_node(Table *table, Row &row, Node *node) {
 	auto *dvl = static_cast<DatabaseValueNode *>(node);
 	ColDefNode col_def = table->get_column_def( dvl->col_name); // TODO optimize it to just get this def once
 	auto db_value = row.ith_column(col_def.order);
@@ -361,7 +355,7 @@ std::unique_ptr<ValueNode> USql::evalDatabaseValueNode(Table *table, Row &row, N
 }
 
 
-std::unique_ptr<ValueNode> USql::evalLiteralValueNode(Table *table, Row &row, Node *node) {
+std::unique_ptr<ValueNode> USql::eval_literal_value_node(Table *table, Row &row, Node *node) {
 	if (node->node_type == NodeType::int_value) {
 		auto *ivl = static_cast<IntValueNode *>(node);
 		return std::make_unique<IntValueNode>(ivl->value);
@@ -380,12 +374,12 @@ std::unique_ptr<ValueNode> USql::evalLiteralValueNode(Table *table, Row &row, No
 }
 
 
-std::unique_ptr<ValueNode> USql::evalFunctionValueNode(Table *table, Row &row, Node *node) {
+std::unique_ptr<ValueNode> USql::eval_function_value_node(Table *table, Row &row, Node *node) {
 	auto  *fnc = static_cast<FunctionNode *>(node);
 
 	std::vector<std::unique_ptr<ValueNode>> evaluatedPars;
 	for(auto & param : fnc->params) {
-		evaluatedPars.push_back(evalValueNode(table, row, param.get()));
+		evaluatedPars.push_back(eval_value_node(table, row, param.get()));
 	}
 
 	// TODO use some enum
@@ -417,24 +411,24 @@ std::unique_ptr<ValueNode> USql::evalFunctionValueNode(Table *table, Row &row, N
 }
 
 
-bool USql::evalLogicalOperator(LogicalOperatorNode &node, Table *pTable, Row &row) const {
+bool USql::eval_logical_operator(LogicalOperatorNode &node, Table *pTable, Row &row) const {
-	bool left = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.left), pTable, row);
+	bool left = eval_relational_operator(static_cast<const RelationalOperatorNode &>(*node.left), pTable, row);
 
 	if ((node.op == LogicalOperatorType::and_operator && !left) || (node.op == LogicalOperatorType::or_operator && left))
 		return left;
 
-	bool right = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.right), pTable, row);
+	bool right = eval_relational_operator(static_cast<const RelationalOperatorNode &>(*node.right), pTable, row);
 	return right;
 }
 
 
-std::unique_ptr<ValueNode> USql::evalArithmeticOperator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const {
+std::unique_ptr<ValueNode> USql::eval_arithmetic_operator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const {
 	if (node.op == ArithmeticalOperatorType::copy_value) {
-		return evalValueNode(table, row, node.left.get());
+		return eval_value_node(table, row, node.left.get());
 	}
 
-	std::unique_ptr<ValueNode> left = evalValueNode(table, row, node.left.get());
+	std::unique_ptr<ValueNode> left = eval_value_node(table, row, node.left.get());
-	std::unique_ptr<ValueNode> right = evalValueNode(table, row, node.right.get());
+	std::unique_ptr<ValueNode> right = eval_value_node(table, row, node.right.get());
 
 	if (outType == ColumnType::float_type) {
 		double l = ((ValueNode *) left.get())->getDoubleValue();
@@ -483,16 +477,18 @@ std::unique_ptr<ValueNode> USql::evalArithmeticOperator(ColumnType outType, Arit
 }
 
 
-std::unique_ptr<Table> USql::create_stmt_result_table(long code, const std::string& text) {
+std::unique_ptr<Table> USql::create_stmt_result_table(long code, const std::string &text, long affected_rows) {
 	std::vector<ColDefNode> result_tbl_col_defs{};
 	result_tbl_col_defs.push_back(ColDefNode("code", ColumnType::integer_type, 0, 1, false));
 	result_tbl_col_defs.push_back(ColDefNode("desc", ColumnType::varchar_type, 1, 255, false));
+	result_tbl_col_defs.push_back(ColDefNode("affected_rows", ColumnType::integer_type, 0, 1, true));
 
 	auto table_def = std::make_unique<Table>("result", result_tbl_col_defs);
 
 	Row new_row = table_def->create_empty_row();
 	new_row.setColumnValue(0, code);
 	new_row.setColumnValue(1, text);
+	new_row.setColumnValue(2, affected_rows);
 	table_def->add_row(new_row);
 
 	return std::move(table_def);

usql.h

@@ -21,29 +21,31 @@ private:
 
     std::unique_ptr<Table> execute_create_table(CreateTableNode &node);
     std::unique_ptr<Table> execute_create_table_as_table(CreateTableAsSelectNode &node);
+    std::unique_ptr<Table> execute_load(LoadIntoTableNode &node);
+    std::unique_ptr<Table> execute_save(SaveTableNode &node);
+    std::unique_ptr<Table> execute_drop(DropTableNode &node);
+
     std::unique_ptr<Table> execute_insert_into_table(InsertIntoTableNode &node);
     std::unique_ptr<Table> execute_select(SelectFromTableNode &node);
     std::unique_ptr<Table> execute_delete(DeleteFromTableNode &node);
     std::unique_ptr<Table> execute_update(UpdateTableNode &node);
-    std::unique_ptr<Table> execute_load(LoadIntoTableNode &node);
-    std::unique_ptr<Table> execute_save(SaveTableNode &node);
 
 
 private:
-    bool evalWhere(Node *where, Table *table, Row &row) const;
+    bool eval_where(Node *where, Table *table, Row &row) const;
 
-    static std::unique_ptr<ValueNode> evalValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> eval_value_node(Table *table, Row &row, Node *node);
-    static std::unique_ptr<ValueNode> evalDatabaseValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> eval_database_value_node(Table *table, Row &row, Node *node);
-    static std::unique_ptr<ValueNode> evalLiteralValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> eval_literal_value_node(Table *table, Row &row, Node *node);
-    static std::unique_ptr<ValueNode> evalFunctionValueNode(Table *table, Row &row, Node *node);
+    static std::unique_ptr<ValueNode> eval_function_value_node(Table *table, Row &row, Node *node);
 
 
-    bool evalRelationalOperator(const RelationalOperatorNode &filter, Table *table, Row &row) const;
+    bool eval_relational_operator(const RelationalOperatorNode &filter, Table *table, Row &row) const;
-    bool evalLogicalOperator(LogicalOperatorNode &node, Table *pTable, Row &row) const;
+    bool eval_logical_operator(LogicalOperatorNode &node, Table *pTable, Row &row) const;
-    std::unique_ptr<ValueNode> evalArithmeticOperator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const;
+    std::unique_ptr<ValueNode> eval_arithmetic_operator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const;
 
 
-    static std::unique_ptr<Table> create_stmt_result_table(long code, const std::string& text);
+    static std::unique_ptr<Table> create_stmt_result_table(long code, const std::string &text, long affected_rows);
     static std::tuple<int, ColDefNode> get_column_definition(Table *table, SelectColNode *select_col_node, int col_order) ;
     Table *find_table(const std::string &name);