table_container

What is a table_container

The table_container class is designed to manage table-like data structures and facilitate operations like selection, removal, filtering, and querying. It provides a flexible and type-safe interface for handling complex data queries.

Obtaining the table_container from a database

To perform a query you need to obtain the table_container object from your database, you can do it by using the container_execute method, this will return a shared pointer pointing to the table_container

Methods

select(std::string number)

Selects a specific record in the table or all records.

• Parameters:

  • number: Record index (string). Use "*" for all records.

• Returns: A pointer to the current instance.

remove(std::string number)

Marks specific records for removal based on the index.

• Parameters:

  • number: Record index (string). Use "*" to mark all records.

• Returns: A pointer to the current instance.

from(std::string table_to_query)

Specifies the table to query and loads its data.

• Parameters:

  • table_to_query: Name of the table to query.

• Returns: A pointer to the current instance.

where(std::string value, std::any is, bool is_not = false)

Filters data rows based on a condition.

• Parameters:

  • value: Column name to filter on.

  • is: Value to compare against.

  • is_not: Whether to invert the condition (default: false).

• Returns: A pointer to the current instance.

get_output()

Retrieves filtered results or deletes records (depending on the operation).

• Returns: A table_vec containing the filtered records.

Supported Data Types

The class supports the following data types:

• INT

• DOUBLE

• FLOAT

• STRING

• BOOL

Example

#include "qic.h"
#include <any>
#include <chrono> // For time measurement
#include <iostream>
#include <unordered_map>

int main() {
    data_base db;

    // Open the database
    db.open_database("mydatabase.db");

    // Set the number of compiling threads
    db.compiling_threads = 1;

    // Add a table to the database
    auto op = db.add_table(
        "COMPANY",
        std::unordered_map<std::string, data_type>{
            {"ID", INT},
            {"NAME", STRING},
            {"AGE", INT},
            {"ADDRESS", STRING},
            {"SALARY", DOUBLE}
        }
    );

    // If adding the table fails, load the existing table
    if (op.stat == FAILED) {
        db.load_table("COMPANY");
    }

    // Remove entries from the "COMPANY" table
    db.container_execute()->remove("*")->from("COMPANY")->get_output();

    // Query the "COMPANY" table
    auto result = db.container_execute()->select("*")->from("COMPANY")->get_output();

    // Display the query results
    for (const auto& query_result : result) {
        std::cout << "------------------------" << std::endl;
        std::cout << "ID : " << std::any_cast<int>(query_result.at("ID")) << std::endl;
        std::cout << "NAME : " << std::any_cast<std::string>(query_result.at("NAME")) << std::endl;
        std::cout << "AGE : " << std::any_cast<int>(query_result.at("AGE")) << std::endl;
        std::cout << "ADDRESS : " << std::any_cast<std::string>(query_result.at("ADDRESS")) << std::endl;
        std::cout << "SALARY : " << std::any_cast<double>(query_result.at("SALARY")) << std::endl;
        std::cout << "------------------------" << std::endl;
    }

    // Save the database
    db.save();

    // Pause execution until user input
    char pause;
    std::cin >> pause;

    // Close the database
    db.close();

    return 0;
}