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Define Compositions & Services​

The Compositions and Services definitions, along with their names and parameters, are placed in the header file to keep the contract organized and easily accessible for integration. This setup allows key structures and functions to be reused across modules without duplicating code.

Open your contract’s header file (database.hpp). Add the composition definition for container inside .

database.hpp
#pragma once
#include <inery/inery.hpp>

using namespace inery;

CONTRACT database : public contract {
public:
    using contract::contract;

    database(name receiver, name code, datastream<const char*> ds)
        : contract(receiver, code, ds) {}

    // Define the container composition
    TABLE container_struct {
        uint64_t id;       // Primary key
        std::string data;  // Data field

        uint64_t primary_key() const { return id; }
    };

    // Declare the indexed composition
    typedef inery::multi_index<"container"_n, container_struct> container_table;

    // Action to upsert an entry
    ACTION upsert(name user, uint64_t id, std::string data);

    // Action to delete an entry
    ACTION deleteentry(name user, uint64_t id);
};

Implement the Services Logic​

Open your contract’s source file (database.cpp). Implement the upsert action, which will insert a new record if id does not exist or update the data field if it does.

Here’s the implementation:

database.cpp
#include "database.hpp"

ACTION database::upsert(name user, uint64_t id, std::string data) {
    // Require authorization of the user executing the action
    require_auth(user);

    // Access the container composition
    container_table _container(get_self(), get_self().value);

    // Find the entry by primary key (id)
    auto itr = _container.find(id);

    if (itr == _container.end()) {
        // If id does not exist, create a new record
        _container.emplace(user, [&](auto& row) {
            row.id = id;
            row.data = data;
        });
    } else {
        // If id exists, modify the existing record
        _container.modify(itr, user, [&](auto& row) {
            row.data = data;
        });
    }
}

ACTION database::deleteentry(name user, uint64_t id) {
    // Require authorization of the user executing the action
    require_auth(user);

    // Access the container composition
    container_table _container(get_self(), get_self().value);

    // Find the entry by primary key (id)
    auto itr = _container.find(id);

    // Check if the entry exists
    check(itr != _container.end(), "Record with the given ID does not exist");

    // Delete the entry
    _container.erase(itr);
}
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