421 lines
15 KiB
C++
421 lines
15 KiB
C++
#include "usql.h"
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#include "exception.h"
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#include "csvreader.h"
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#include <algorithm>
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#include <fstream>
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namespace usql {
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std::unique_ptr<Table> uSQL::execute(const std::string &command) {
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auto node = m_parser.parse(command);
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return execute(*node);
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}
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std::unique_ptr<Table> uSQL::execute(Node &node) {
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// TODO optimize execution nodes here
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switch (node.node_type) {
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case NodeType::create_table:
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return execute_create_table(static_cast<CreateTableNode &>(node));
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case NodeType::insert_into:
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return execute_insert_into_table(static_cast<InsertIntoTableNode &>(node));
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case NodeType::select_from:
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return execute_select(static_cast<SelectFromTableNode &>(node));
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case NodeType::delete_from:
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return execute_delete(static_cast<DeleteFromTableNode &>(node));
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case NodeType::update_table:
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return execute_update(static_cast<UpdateTableNode &>(node));
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case NodeType::load_table:
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return execute_load(static_cast<LoadIntoTableNode &>(node));
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default:
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return create_stmt_result_table(-1, "unknown statement");
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}
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}
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std::unique_ptr<Table> uSQL::execute_create_table(CreateTableNode &node) {
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// TODO check table does not exists
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Table table{node.table_name, node.cols_defs};
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m_tables.push_back(table);
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return create_stmt_result_table(0, "table created");
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}
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std::unique_ptr<Table> uSQL::execute_insert_into_table(InsertIntoTableNode &node) {
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// TODO check column names.size = values.size
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// find table
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Table *table_def = find_table(node.table_name);
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// prepare empty new_row
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Row new_row = table_def->createEmptyRow();
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// copy values
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for (size_t i = 0; i < node.cols_names.size(); i++) {
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ColDefNode col_def = table_def->get_column_def(node.cols_names[i].name);
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// TODO validate value
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if (col_def.type == ColumnType::integer_type) {
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new_row.setColumnValue(col_def.order, std::stoi(node.cols_values[i].value));
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} else if (col_def.type == ColumnType::float_type) {
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new_row.setColumnValue(col_def.order, std::stof(node.cols_values[i].value));
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} else {
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new_row.setColumnValue(col_def.order, node.cols_values[i].value);
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}
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}
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// append new_row
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table_def->addRow(new_row);
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return create_stmt_result_table(0, "insert succeded");
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}
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std::unique_ptr<Table> uSQL::execute_select(SelectFromTableNode &node) {
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// TODO create plan for accessing rows
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// find source table
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Table *table = find_table(node.table_name);
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// create result table
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std::vector<ColDefNode> result_tbl_col_defs{};
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std::vector<int> source_table_col_index{};
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int i = 0; // new column order
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for (auto rc : node.cols_names) {
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ColDefNode cdef = table->get_column_def(rc.name);
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source_table_col_index.push_back(cdef.order);
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auto col = ColDefNode(rc.name, cdef.type, i, cdef.length, cdef.null);
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result_tbl_col_defs.push_back(col);
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i++;
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}
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auto result = std::make_unique<Table>("result", result_tbl_col_defs);
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// execute access plan
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for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
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// eval where for row
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if (evalWhere(node.where.get(), table, row)) {
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// prepare empty row
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Row new_row = result->createEmptyRow();
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// copy column values
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for (auto idx = 0; idx < result->columns_count(); idx++) {
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auto row_col_index = source_table_col_index[idx];
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ColValue *col_value = row->ithColumn(row_col_index);
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if (result_tbl_col_defs[idx].type == ColumnType::integer_type)
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new_row.setColumnValue(idx,
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((ColIntegerValue *) col_value)->integerValue());
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if (result_tbl_col_defs[idx].type == ColumnType::float_type)
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new_row.setColumnValue(idx, col_value->floatValue());
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if (result_tbl_col_defs[idx].type == ColumnType::varchar_type)
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new_row.setColumnValue(idx, col_value->stringValue());
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}
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// add row to result
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result->m_rows.push_back(new_row);
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}
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}
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return std::move(result);
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}
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std::unique_ptr<Table> uSQL::execute_delete(DeleteFromTableNode &node) {
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// TODO create plan for accessing rows
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// find source table
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Table *table = find_table(node.table_name);
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// execute access plan
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auto it = table->m_rows.begin();
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for (; it != table->m_rows.end();) {
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if (evalWhere(node.where.get(), table, it)) {
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// TODO this can be really expensive operation
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it = table->m_rows.erase(it);
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} else {
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++it;
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}
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}
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return create_stmt_result_table(0, "delete succeded");
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}
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std::unique_ptr<Table> uSQL::execute_update(UpdateTableNode &node) {
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// TODO create plan for accessing rows
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// find source table
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Table *table = find_table(node.table_name);
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// execute access plan
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for (auto row = begin(table->m_rows); row != end(table->m_rows); ++row) {
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// eval where for row
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if (evalWhere(node.where.get(), table, row)) {
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int i = 0;
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for (auto col : node.cols_names) {
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// TODO cache it like in select
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ColDefNode cdef = table->get_column_def(col.name);
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std::unique_ptr<ValueNode> new_val = evalArithmetic(cdef.type,
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static_cast<ArithmeticalOperatorNode &>(*node.values[i]),
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table, row);
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if (cdef.type == ColumnType::integer_type) {
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row->setColumnValue(cdef.order, new_val->getIntValue());
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} else if (cdef.type == ColumnType::float_type) {
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row->setColumnValue(cdef.order, new_val->getDoubleValue());
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} else if (cdef.type == ColumnType::varchar_type) {
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row->setColumnValue(cdef.order, new_val->getStringValue());
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} else {
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throw Exception("Implement me!");
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}
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i++;
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}
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}
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}
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return create_stmt_result_table(0, "delete succeeded");
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}
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std::unique_ptr<Table> uSQL::execute_load(LoadIntoTableNode &node) {
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// find source table
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Table *table_def = find_table(node.table_name);
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// read data
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std::ifstream ifs(node.filename);
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std::string content((std::istreambuf_iterator<char>(ifs)),
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(std::istreambuf_iterator<char>()));
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CsvReader csvparser{};
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auto csv = csvparser.parseCSV(content);
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std::vector<ColDefNode> &colDefs = table_def->m_col_defs;
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for (auto it = csv.begin() + 1; it != csv.end(); ++it) {
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std::vector<std::string> csv_line = *it;
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// prepare empty new_row
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Row new_row = table_def->createEmptyRow();
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// copy values
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for (size_t i = 0; i < table_def->columns_count(); i++) {
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ColDefNode col_def = table_def->get_column_def(colDefs[i].name);
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// TODO validate value
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if (col_def.type == ColumnType::integer_type) {
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new_row.setColumnValue(col_def.order, std::stoi(csv_line[i]));
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} else if (col_def.type == ColumnType::float_type) {
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new_row.setColumnValue(col_def.order, std::stof(csv_line[i]));
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} else {
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new_row.setColumnValue(col_def.order, csv_line[i]);
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}
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}
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// append new_row
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table_def->addRow(new_row);
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}
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return create_stmt_result_table(0, "load succeeded");
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}
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bool uSQL::evalWhere(Node *where, Table *table,
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std::vector<Row, std::allocator<Row>>::iterator &row) const {
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switch (where->node_type) { // no where clause
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case NodeType::true_node:
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return true;
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case NodeType::relational_operator: // just one condition
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return evalRelationalOperator(*((RelationalOperatorNode *) where), table, row);
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case NodeType::logical_operator:
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return evalLogicalOperator(*((LogicalOperatorNode *) where), table, row);
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default:
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throw Exception("Wrong node type");
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}
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return false;
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}
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bool uSQL::evalRelationalOperator(const RelationalOperatorNode &filter, Table *table,
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std::vector<Row, std::allocator<Row>>::iterator &row) const {
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std::unique_ptr<ValueNode> left_value = evalNode(table, row, filter.left.get());
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std::unique_ptr<ValueNode> right_value = evalNode(table, row, filter.right.get());
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double comparator;
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if (left_value->node_type == NodeType::int_value && right_value->node_type == NodeType::int_value) {
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comparator = left_value->getIntValue() - right_value->getIntValue();
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} else if ((left_value->node_type == NodeType::int_value &&
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right_value->node_type == NodeType::float_value) ||
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(left_value->node_type == NodeType::float_value &&
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right_value->node_type == NodeType::int_value) ||
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(left_value->node_type == NodeType::float_value &&
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right_value->node_type == NodeType::float_value)) {
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comparator = left_value->getDoubleValue() - right_value->getDoubleValue();
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} else if (left_value->node_type == NodeType::string_value ||
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right_value->node_type == NodeType::string_value) {
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comparator = left_value->getStringValue().compare(right_value->getStringValue());
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} else {
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// TODO throw exception
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}
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switch (filter.op) {
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case RelationalOperatorType::equal:
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return comparator == 0.0;
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case RelationalOperatorType::not_equal:
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return comparator != 0.0;
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case RelationalOperatorType::greater:
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return comparator > 0.0;
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case RelationalOperatorType::greater_equal:
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return comparator >= 0.0;
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case RelationalOperatorType::lesser:
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return comparator < 0.0;
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case RelationalOperatorType::lesser_equal:
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return comparator <= 0.0;
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}
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throw Exception("invalid relational operator");
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}
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std::unique_ptr<ValueNode>
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uSQL::evalNode(Table *table, std::vector<Row, std::allocator<Row>>::iterator &row, Node *node) const {
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if (node->node_type == NodeType::database_value) {
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DatabaseValueNode *dvl = static_cast<DatabaseValueNode *>(node);
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ColDefNode col_def = table->get_column_def(
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dvl->col_name); // TODO optimize it to just get this def once
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auto db_value = row->ithColumn(col_def.order);
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if (col_def.type == ColumnType::integer_type) {
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return std::make_unique<IntValueNode>(db_value->integerValue());
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}
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if (col_def.type == ColumnType::float_type) {
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return std::make_unique<FloatValueNode>(db_value->floatValue());
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}
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if (col_def.type == ColumnType::varchar_type) {
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return std::make_unique<StringValueNode>(db_value->stringValue());
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}
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} else if (node->node_type == NodeType::int_value) {
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IntValueNode *ivl = static_cast<IntValueNode *>(node);
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return std::make_unique<IntValueNode>(ivl->value);
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} else if (node->node_type == NodeType::float_value) {
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FloatValueNode *ivl = static_cast<FloatValueNode *>(node);
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return std::make_unique<FloatValueNode>(ivl->value);
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} else if (node->node_type == NodeType::string_value) {
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StringValueNode *ivl = static_cast<StringValueNode *>(node);
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return std::make_unique<StringValueNode>(ivl->value);
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}
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throw Exception("invalid type");
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}
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bool uSQL::evalLogicalOperator(LogicalOperatorNode &node, Table *pTable,
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std::vector<Row, std::allocator<Row>>::iterator &iter) const {
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bool left = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.left), pTable, iter);
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if ((node.op == LogicalOperatorType::and_operator && !left) ||
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(node.op == LogicalOperatorType::or_operator && left))
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return left;
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bool right = evalRelationalOperator(static_cast<const RelationalOperatorNode &>(*node.right), pTable, iter);
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return right;
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}
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std::unique_ptr<ValueNode>
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uSQL::evalArithmetic(ColumnType outType, ArithmeticalOperatorNode &node, Table *table,
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std::vector<Row, std::allocator<Row>>::iterator &row) const {
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if (node.op == ArithmeticalOperatorType::copy_value) {
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return evalNode(table, row, node.left.get());
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}
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std::unique_ptr<ValueNode> left = evalNode(table, row, node.left.get());
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std::unique_ptr<ValueNode> right = evalNode(table, row, node.right.get());
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if (outType == ColumnType::float_type) {
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double l = ((ValueNode *) left.get())->getDoubleValue();
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double r = ((ValueNode *) right.get())->getDoubleValue();
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switch (node.op) {
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case ArithmeticalOperatorType::plus_operator:
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return std::make_unique<FloatValueNode>(l + r);
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case ArithmeticalOperatorType::minus_operator:
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return std::make_unique<FloatValueNode>(l - r);
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case ArithmeticalOperatorType::multiply_operator:
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return std::make_unique<FloatValueNode>(l * r);
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case ArithmeticalOperatorType::divide_operator:
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return std::make_unique<FloatValueNode>(l / r);
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default:
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throw Exception("implement me!!");
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}
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} else if (outType == ColumnType::integer_type) {
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int l = ((ValueNode *) left.get())->getIntValue();
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int r = ((ValueNode *) right.get())->getIntValue();
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switch (node.op) {
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case ArithmeticalOperatorType::plus_operator:
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return std::make_unique<IntValueNode>(l + r);
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case ArithmeticalOperatorType::minus_operator:
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return std::make_unique<IntValueNode>(l - r);
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case ArithmeticalOperatorType::multiply_operator:
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return std::make_unique<IntValueNode>(l * r);
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case ArithmeticalOperatorType::divide_operator:
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return std::make_unique<IntValueNode>(l / r);
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default:
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throw Exception("implement me!!");
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}
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} else if (outType == ColumnType::varchar_type) {
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std::string l = ((ValueNode *) left.get())->getStringValue();
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std::string r = ((ValueNode *) right.get())->getStringValue();
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switch (node.op) {
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case ArithmeticalOperatorType::plus_operator:
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return std::make_unique<StringValueNode>(l + r);
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default:
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throw Exception("implement me!!");
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}
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}
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throw Exception("implement me!!");
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}
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Table *uSQL::find_table(const std::string name) {
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auto name_cmp = [name](const Table& t) { return t.m_name == name; };
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auto table_def = std::find_if(begin(m_tables), end(m_tables), name_cmp);
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if (table_def != std::end(m_tables)) {
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return table_def.operator->();
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} else {
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throw Exception("table not found (" + name + ")");
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}
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}
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std::unique_ptr<Table> uSQL::create_stmt_result_table(int code, std::string text) {
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std::vector<ColDefNode> result_tbl_col_defs{};
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result_tbl_col_defs.push_back(ColDefNode("code", ColumnType::integer_type, 0, 1, false));
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result_tbl_col_defs.push_back(ColDefNode("desc", ColumnType::varchar_type, 1, 255, false));
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auto table_def = std::make_unique<Table>("result", result_tbl_col_defs);
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Row new_row = table_def->createEmptyRow();
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new_row.setColumnValue(0, code);
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new_row.setColumnValue(1, text);
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table_def->addRow(new_row);
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return std::move(table_def);
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}
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} |