Add database schema supporting multiple water meters per consumer

[Copilot]

Current schema ties readings and images directly to consumers, preventing scenarios where one consumer has multiple water meters at different locations.

Schema Changes

consumers table

• Added customer_code VARCHAR(50) UNIQUE NOT NULL for external customer identification

water_meters table (new)

• Links consumers to their meters (1:N relationship)
• meter_code VARCHAR(50) UNIQUE NOT NULL - unique meter identifier
• location VARCHAR(255) - physical location of meter
• is_active BOOLEAN - supports meter lifecycle management
• Foreign key: consumer_id → consumers(id)

images and readings tables

• Changed foreign key from consumer_id to water_meter_id
• Links readings/images to specific meters instead of consumers

Sample Data

-- Consumer K-001 has two meters at different locations
INSERT INTO water_meters (consumer_id, meter_code, location, installation_date) VALUES
    ((SELECT id FROM consumers WHERE customer_code = 'K-001'), 'VM-001-A', 'Glavni vodomer', '2024-01-15'),
    ((SELECT id FROM consumers WHERE customer_code = 'K-001'), 'VM-001-B', 'Vodomer u bašti', '2024-01-15');

Future Work

Application code (database.py, main.py) needs updates to use water_meter_id instead of consumer_id.

Original prompt

Problem

Trenutna struktura baze podataka ne podržava sledeće scenarije:

• Jedan korisnik može imati više vodomera koje treba očitati
• Nedostaje šifra korisnika (customer_code) za jedinstvenu identifikaciju
• Očitavanja i slike su direktno vezane za korisnika umesto za konkretan vodomer

Rešenje

Potrebno je ažurirati init.sql fajl sa sledećim promenama:

1. Ažurirati consumers tabelu

Dodati kolonu customer_code za jedinstvenu šifru korisnika:

CREATE TABLE IF NOT EXISTS consumers (
    id INT PRIMARY KEY AUTO_INCREMENT,
    customer_code VARCHAR(50) UNIQUE NOT NULL,
    name VARCHAR(255) NOT NULL,
    address VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

2. Kreirati novu tabelu water_meters

Dodati novu tabelu koja omogućava da jedan korisnik ima više vodomera:

CREATE TABLE IF NOT EXISTS water_meters (
    id INT PRIMARY KEY AUTO_INCREMENT,
    consumer_id INT NOT NULL,
    meter_code VARCHAR(50) UNIQUE NOT NULL,
    location VARCHAR(255),
    installation_date DATE,
    is_active TINYINT DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (consumer_id) REFERENCES consumers(id)
);

3. Ažurirati images tabelu

Promeniti foreign key sa consumer_id na water_meter_id:

CREATE TABLE IF NOT EXISTS images (
    id INT PRIMARY KEY AUTO_INCREMENT,
    water_meter_id INT NOT NULL,
    image_url VARCHAR(512) NOT NULL,
    processed TINYINT DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (water_meter_id) REFERENCES water_meters(id)
);

4. Ažurirati readings tabelu

Promeniti foreign key sa consumer_id na water_meter_id:

CREATE TABLE IF NOT EXISTS readings (
    id INT PRIMARY KEY AUTO_INCREMENT,
    water_meter_id INT NOT NULL,
    reading_value DECIMAL(10,2),
    image_path VARCHAR(512),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (water_meter_id) REFERENCES water_meters(id)
);

5. Ažurirati test podatke

Primer podataka koji demonstrira scenario gde jedan korisnik ima više vodomera:

-- Insert sample consumers
INSERT INTO consumers (customer_code, name, address) VALUES 
    ('K-001', 'Petar Petrović', 'Kralja Petra 1, Beograd'),
    ('K-002', 'Marija Marković', 'Bulevar oslobođenja 23, Novi Sad'),
    ('K-003', 'Jovan Jovanović', 'Kneza Miloša 45, Niš');

-- Insert sample water meters (showing consumer K-001 has 2 meters)
INSERT INTO water_meters (consumer_id, meter_code, location, installation_date) VALUES
    (1, 'VM-001-A', 'Glavni vodomer', '2024-01-15'),
    (1, 'VM-001-B', 'Vodomer u bašti', '2024-01-15'),
    (2, 'VM-002-A', 'Stan', '2024-02-10'),
    (3, 'VM-003-A', 'Kuća', '2024-03-05');

Benefiti nove strukture

✅ Jedan korisnik može imati više vodomera
✅ Svaki vodomer ima svoju jedinstvenu šifru (meter_code)
✅ Očitavanja su vezana za konkretan vodomer
✅ Lakše praćenje lokacije svakog vodomera
✅ Mogućnost deaktivacije starih vodomera (is_active flag)
✅ Jedinstvena šifra korisnika (customer_code)

Napomena

Ove promene menjaju samo init.sql fajl. Biće potrebno ažurirati i:

• database.py - dodati funkcije za rad sa water_meters tabelom
• main.py - ažurirati endpoint da prima water_meter_id umesto consumer_id

Ali to može biti u sledećem PR-u nakon što se ova struktura odobri.

This pull request was created as a result of the following prompt from Copilot chat.

Problem

Trenutna struktura baze podataka ne podržava sledeće scenarije:

• Jedan korisnik može imati više vodomera koje treba očitati
• Nedostaje šifra korisnika (customer_code) za jedinstvenu identifikaciju
• Očitavanja i slike su direktno vezane za korisnika umesto za konkretan vodomer

Rešenje

Potrebno je ažurirati init.sql fajl sa sledećim promenama:

1. Ažurirati consumers tabelu

Dodati kolonu customer_code za jedinstvenu šifru korisnika:

CREATE TABLE IF NOT EXISTS consumers (
    id INT PRIMARY KEY AUTO_INCREMENT,
    customer_code VARCHAR(50) UNIQUE NOT NULL,
    name VARCHAR(255) NOT NULL,
    address VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

2. Kreirati novu tabelu water_meters

Dodati novu tabelu koja omogućava da jedan korisnik ima više vodomera:

CREATE TABLE IF NOT EXISTS water_meters (
    id INT PRIMARY KEY AUTO_INCREMENT,
    consumer_id INT NOT NULL,
    meter_code VARCHAR(50) UNIQUE NOT NULL,
    location VARCHAR(255),
    installation_date DATE,
    is_active TINYINT DEFAULT 1,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (consumer_id) REFERENCES consumers(id)
);

3. Ažurirati images tabelu

Promeniti foreign key sa consumer_id na water_meter_id:

CREATE TABLE IF NOT EXISTS images (
    id INT PRIMARY KEY AUTO_INCREMENT,
    water_meter_id INT NOT NULL,
    image_url VARCHAR(512) NOT NULL,
    processed TINYINT DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (water_meter_id) REFERENCES water_meters(id)
);

4. Ažurirati readings tabelu

Promeniti foreign key sa consumer_id na water_meter_id:

CREATE TABLE IF NOT EXISTS readings (
    id INT PRIMARY KEY AUTO_INCREMENT,
    water_meter_id INT NOT NULL,
    reading_value DECIMAL(10,2),
    image_path VARCHAR(512),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (water_meter_id) REFERENCES water_meters(id)
);

5. Ažurirati test podatke

Primer podataka koji demonstrira scenario gde jedan korisnik ima više vodomera:

-- Insert sample consumers
INSERT INTO consumers (customer_code, name, address) VALUES 
    ('K-001', 'Petar Petrović', 'Kralja Petra 1, Beograd'),
    ('K-002', 'Marija Marković', 'Bulevar oslobođenja 23, Novi Sad'),
    ('K-003', 'Jovan Jovanović', 'Kneza Miloša 45, Niš');

-- Insert sample water meters (showing consumer K-001 has 2 meters)
INSERT INTO water_meters (consumer_id, meter_code, location, installation_date) VALUES
    (1, 'VM-001-A', 'Glavni vodomer', '2024-01-15'),
    (1, 'VM-001-B', 'Vodomer u bašti', '2024-01-15'),
    (2, 'VM-002-A', 'Stan', '2024-02-10'),
    (3, 'VM-003-A', 'Kuća', '2024-03-05');

Benefiti nove strukture

✅ Jedan korisnik može imati više vodomera
✅ Svaki vodomer ima svoju jedinstvenu šifru (meter_code)
✅ Očitavanja su vezana za konkretan vodomer
✅ Lakše praćenje lokacije svakog vodomera
✅ Mogućnost deaktivacije starih vodomera (is_active flag)
✅ Jedinstvena šifra korisnika (customer_code)

Napomena

Ove promene menjaju samo init.sql fajl. Biće potrebno ažurirati i:

• database.py - dodati funkcije za rad sa water_meters tabelom
• main.py - ažurirati endpoint da prima water_meter_id umesto consumer_id

Ali to može biti u sledećem PR-u nakon što se ova struktura odobri.

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