jzwsqlbase/database.cpp at main · XDjzw/jzwsqlbase · GitHub

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#include "database.h"
#include "common.h"
#include <iostream>
#include <filesystem>
#include <map>
#include "table.h"


bool createDatabase(const std::string& dbName) {
   std::string dbPath = getDatabasePath(dbName);


    if (fileExists(dbPath)) {
        std::cerr << "Error: Database already exists." << std::endl;
        return false;
    }


    try {
        std::filesystem::create_directory(dbPath);
    } catch (const std::filesystem::filesystem_error& e) {
        std::cerr << "Error: Failed to create database directory - " << e.what() << std::endl;
        return false;
    }


    databases[dbName];

    flushMetaFile(dbName);

    std::cout << "Database created successfully: " << dbName << std::endl;
    return true;
}


bool dropDatabase(const std::string& dbName) {
    std::string dbPath = getDatabasePath(dbName);
    if (!fileExists(dbPath)) {
        std::cerr << "Error: Database does not exist." << std::endl;
        return false;
    }
    std::filesystem::remove_all(dbPath);
    std::cout << "Database dropped successfully." << std::endl;
    return true;
}


bool useDatabase(const std::string& dbName) {
std::string dbPath = getDatabasePath(dbName);
    if (!fileExists(dbPath)) {
        std::cerr << "Error: Database does not exist." << std::endl;
        return false;
    }

    currentDatabase = dbName;


    auto it = databases.find(currentDatabase);
    if (it == databases.end()) {
        databases[currentDatabase] = std::map<std::string, Table>();

    }

    reloadTablesForCurrentDatabase();

    return true;
}
void reloadTablesForCurrentDatabase() {
 auto dbIt = databases.find(currentDatabase);
    if (dbIt == databases.end()) {
        std::cerr << "Error: Current database not found in memory." << std::endl;
        return;
    }

    dbIt->second.clear();

    std::string dbPath = getDatabasePath(currentDatabase);

    for (const auto& entry : std::filesystem::directory_iterator(dbPath)) {
        if (entry.is_regular_file() && entry.path().extension() == ".csv") {
            std::string tableName = entry.path().stem().string();
            Table newTable;
            if (loadTableFromDisk(currentDatabase, tableName, &newTable)) {
                dbIt->second[tableName] = std::move(newTable);
            }
        }
    }
}

std::vector<std::string> showDatabases() {
    std::vector<std::string> databases;
    for (const auto& entry : std::filesystem::directory_iterator(workPath)) {
        if (entry.is_directory()) {
            databases.push_back(entry.path().filename().string());
        }
    }
    return databases;
}