HM JDBC #418

dlvsn · 2024-09-21T22:35:09Z

No description provided.

mateacademy-ai-mentor

Hey there! 😊 It looks like there are a few critical issues that need addressing before we can merge your Pull Request. Specifically, the database URL needs to be complete to ensure the application can connect to the database, and the deleteById method should reflect the actual result of the operation. Additionally, remember to use consistent naming for your tables according to the SQL style guide. Keep up the great work, and once these changes are made, your code will be in excellent shape! 🚀

✨ Please rate this review in the Platform's notification center. I will be grateful for your feedback! ✨

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+    @Override
+    public int getRowsCount() {
+        String sql = "SELECT COUNT(*) AS total_rows FROM book";


The table name should be books instead of book according to the SQL style guide in the checklist.

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+    @Override
+    public boolean clear() {
+        String sql = "TRUNCATE TABLE book";


The table name should be books instead of book according to the SQL style guide in the checklist.

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+        try (Connection connection = ConnectionUtil.getConnection();
+                        Statement statement = connection.createStatement()) {
+            int affectedRows = statement.executeUpdate(sql);
+            return affectedRows >= getRowsCount();


Using getRowsCount() after truncating the table to check if the operation was successful is incorrect, as the row count will always be 0 after a truncate operation. You should instead check if affectedRows is not negative to indicate success.

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+    @Override
+    public Book create(Book book) {
+        String sql = "INSERT INTO book(title, price) VALUES(?, ?)";


The table name should be books instead of book according to the SQL style guide in the checklist.

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+    public Book create(Book book) {
+        String sql = "INSERT INTO book(title, price) VALUES(?, ?)";
+        try (Connection connection = ConnectionUtil.getConnection();
+                        PreparedStatement statement = connection


Please use PreparedStatement instead of Statement for this query as per the best practices mentioned in the checklist.

mateacademy-ai-mentor · 2024-09-21T22:35:31Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+    @Override
+    public boolean deleteById(Long id) {
+        String sql = "DELETE FROM book WHERE id = ?";


The table name should be books instead of book according to the SQL style guide in the checklist. Also, for the deleteById method, you should return a boolean value depending on preparedStatement.executeUpdate() result, not just true all the time.

mateacademy-ai-mentor · 2024-09-21T22:35:32Z

src/main/java/mate/academy/dbconnection/ConnectionUtil.java

+import java.util.Properties;
+
+public class ConnectionUtil {
+    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";


The DB_URL is incomplete and missing the actual database URL. It should be a full JDBC URL of the form jdbc:mysql://:/<database_name>, for example: "jdbc:mysql://localhost:3306/my_database".

mateacademy-ai-mentor · 2024-09-21T22:35:32Z

src/main/java/mate/academy/model/Book.java

+    private Book(long id, String title, int price) {
+        this.id = id;
+        this.title = title;
+        this.price = price;
+    }


It's not consistent to use both a constructor and setters for object initialization. Since you have setters for all fields, consider using a no-argument constructor and initializing fields through setters, or remove the setters and use only the constructor for initialization.

mateacademy-ai-mentor · 2024-09-21T22:35:32Z

src/main/java/mate/academy/model/Book.java

+    private Book(String title, int price) {
+        this.title = title;
+        this.price = price;
+    }


The overloaded private constructor is not necessary if you're using factory methods. You can have a single private constructor and handle object creation entirely through the static factory methods of.

mateacademy-ai-mentor · 2024-09-21T22:35:32Z

src/main/java/mate/academy/model/Book.java

+    public static Book of(long id, String title, int price) {
+        return new Book(id, title, price);
+    }
+
+    public static Book of(String title, int price) {
+        return new Book(title, price);


According to the checklist, when converting a ResultSet to a Book object, it's better to create an object using setters or a constructor but not both. Since you have provided factory methods, consider removing the setters and making the fields final to ensure immutability of the Book objects once created.

mateacademy-ai-mentor

Great job on implementing the BookDao interface with CRUD operations! 👏 Remember to consistently use PreparedStatement for all your queries, manage resources effectively by closing ResultSet objects, and handle the results of update and delete operations properly. Keep up the good work, and always consider security best practices, like not storing sensitive information in your code. Keep learning and coding! 🚀

✨ Please rate this review in the Platform's notification center. I will be grateful for your feedback! ✨

mateacademy-ai-mentor · 2024-09-22T05:21:23Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+    public boolean clear() {
+        String sql = "TRUNCATE TABLE books";
+        try (Connection connection = ConnectionUtil.getConnection();
+                        Statement statement = connection.createStatement()) {


Use PreparedStatement over Statement, even for a static query with no parameters in clear() method. It's the best practice, and it's slightly faster.

mateacademy-ai-mentor · 2024-09-22T05:21:24Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+        try (Connection connection = ConnectionUtil.getConnection();
+                        Statement statement = connection.createStatement()) {
+            statement.executeUpdate(sql);
+            return true;


Instead of returning true all the time, let's return boolean value depending on statement.executeUpdate() result.

mateacademy-ai-mentor · 2024-09-22T05:21:24Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+    @Override
+    public Book create(Book book) {
+        String sql = "INSERT INTO books(title, price) VALUES(?, ?)";


Use Statement.RETURN_GENERATED_KEYS only in create statement. Since this is the create method, it's correctly used here. However, ensure it's not used in other methods where it's not needed.

mateacademy-ai-mentor · 2024-09-22T05:21:24Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+            ResultSet generatedKeys = preparedStatement.getGeneratedKeys();
+            if (generatedKeys.next()) {
+                long id = generatedKeys.getLong(1);
+                book.setId(id);
+            }


The ResultSet for generated keys should be closed to avoid any potential resource leaks. You can include it in the try-with-resources statement.

mateacademy-ai-mentor · 2024-09-22T05:21:24Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+        String sql = "SELECT * FROM books WHERE id = ?";
+        try (Connection connection = ConnectionUtil.getConnection();
+                        PreparedStatement preparedStatement = connection
+                                .prepareStatement(sql)) {


Use PreparedStatement over Statement. Since you're already using PreparedStatement, this is just a reminder to maintain this practice.

mateacademy-ai-mentor · 2024-09-22T05:21:24Z

src/main/java/mate/academy/dbconnection/ConnectionUtil.java

+import java.util.Properties;
+
+public class ConnectionUtil {
+    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";


The DB_URL is incomplete. It should contain the full JDBC URL to the database, including the host, port, and database name. For example: jdbc:mysql://localhost:3306/myDatabase

mateacademy-ai-mentor · 2024-09-22T05:21:25Z

src/main/java/mate/academy/dbconnection/ConnectionUtil.java

+
+public class ConnectionUtil {
+    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";
+    private static final Properties DB_PROPERTIES;


It is not secure to store database credentials in code. It's better to use environment variables or a configuration file that is not included in the version control.

mateacademy-ai-mentor · 2024-09-22T05:21:25Z

src/main/java/mate/academy/model/Book.java

+    private Book(long id, String title, int price) {
+        this.id = id;
+        this.title = title;
+        this.price = price;
+    }


It's not consistent to use both ways of initialization of an object. Since you have setters for all fields, you can remove the private constructor and create objects using setters or create a public constructor that initializes all fields.

mateacademy-ai-mentor · 2024-09-22T05:21:25Z

src/main/java/mate/academy/model/Book.java

+    private Book(String title, int price) {
+        this.title = title;
+        this.price = price;
+    }


This constructor should be removed to maintain consistency as mentioned in the previous comment.

mateacademy-ai-mentor · 2024-09-22T05:21:25Z

src/main/java/mate/academy/model/Book.java

+    public static Book of(long id, String title, int price) {
+        return new Book(id, title, price);
+    }
+
+    public static Book of(String title, int price) {
+        return new Book(title, price);
+    }


Factory methods 'of' are generally used to create instances without using the 'new' keyword directly. However, these should be used consistently. If you decide to keep the factory methods, you should also ensure that all objects are created through them for consistency.

Elena-Bruyako · 2024-09-22T18:24:14Z

src/main/java/mate/academy/bookdao/BookDao.java

+import mate.academy.model.Book;
+
+public interface BookDao {
+


Suggested change

Elena-Bruyako · 2024-09-22T18:24:51Z

src/main/java/mate/academy/bookdao/BookDao.java

+    int getRowsCount();
+
+    boolean clear();


Suggested change

int getRowsCount();

boolean clear();

Elena-Bruyako · 2024-09-22T18:25:00Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+
+@Dao
+public class BookDaoImpl implements BookDao {
+


Suggested change

Elena-Bruyako · 2024-09-22T18:26:03Z

src/main/java/mate/academy/Main.java

+
+        bookDao.findById(3L).ifPresent(System.out::println);
+
+        boolean b = bookDao.deleteById(3L);


Elena-Bruyako · 2024-09-22T18:26:18Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+                            Statement statement = connection.createStatement();
+                            ResultSet resultSet = statement.executeQuery(sql)) {
+            while (resultSet.next()) {
+                long id = resultSet.getLong("id");


Suggested change

long id = resultSet.getLong("id");

Long id = resultSet.getLong("id");

Elena-Bruyako · 2024-09-22T18:27:03Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+            preparedStatement.setLong(1, id);
+            ResultSet resultSet = preparedStatement.executeQuery();
+            if (resultSet.next()) {
+                String title = resultSet.getString("title");


use separate method to map resultSet to book

Elena-Bruyako · 2024-09-22T18:27:20Z

src/main/java/mate/academy/model/Book.java

+package mate.academy.model;
+
+public class Book {
+    private long id;


Suggested change

private long id;

private Long id;

Elena-Bruyako · 2024-09-22T18:27:27Z

src/main/java/mate/academy/model/Book.java

+public class Book {
+    private long id;
+    private String title;
+    private int price;


Suggested change

private int price;

private BigDecimal price;

Elena-Bruyako · 2024-09-22T18:27:44Z

src/main/resources/init_db.sql

@@ -0,0 +1,6 @@
+CREATE TABLE book
+(
+    id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,


Suggested change

id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,

id BIGINT PRIMARY KEY AUTO_INCREMENT,

Elena-Bruyako · 2024-09-22T18:27:56Z

src/main/resources/init_db.sql

+(
+    id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
+    title VARCHAR(100) NOT NULL,
+    price  INT NOT NULL


Suggested change

price INT NOT NULL

price DECIMAL NOT NULL

… BigDecimal

Elena-Bruyako · 2024-09-23T12:54:08Z

src/main/java/mate/academy/bookdao/BookDao.java

+import mate.academy.model.Book;
+
+public interface BookDao {
+


remove 8 line

Elena-Bruyako · 2024-09-23T12:55:23Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+            if (storeBook(preparedStatement, book, true)) {
+                throw new RuntimeException("Book not found");
+            }


Suggested change

if (storeBook(preparedStatement, book, true)) {

throw new RuntimeException("Book not found");

}

statement.setString(1, book.getTitle());

statement.setBigDecimal(2, book.getPrice());

statement.setLong(3, book.getId());

if (statement.executeUpdate() < 1) {

throw new DataProcessingException("Update failed for book with id:" + book.getId());

}

Elena-Bruyako · 2024-09-23T12:55:32Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+        return Book.of(id, title, price);
+    }
+
+    private boolean storeBook(PreparedStatement preparedStatement,


Elena-Bruyako · 2024-09-23T12:56:21Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+            if (storeBook(preparedStatement, book, false)) {
+                throw new RuntimeException("Book could not be created");
+            }


Suggested change

if (storeBook(preparedStatement, book, false)) {

throw new RuntimeException("Book could not be created");

}

statement.setString(1, book.getTitle());

statement.setBigDecimal(2, book.getPrice());

if (statement.executeUpdate() < 1) {

Elena-Bruyako · 2024-09-23T12:56:57Z

src/main/java/mate/academy/bookdao/BookDaoImpl.java

+        try (Connection connection = ConnectionUtil.getConnection();
+                        PreparedStatement statement = connection.prepareStatement(sql)) {
+            statement.setLong(1, id);
+            int affectedRow = statement.executeUpdate();


Suggested change

int affectedRow = statement.executeUpdate();

return statement.executeUpdate() > 0;

dlvsn added 15 commits September 19, 2024 00:24

created a init_db.sql and put a script for creating table

69e8344

Implemented class Book

c097cef

added NOT NULL to tittle and price in initDb.sql

4c687e8

Implemented ConnectionUtil

b87ce47

Created bookDao interface and added CRUD methods

f18845a

added mySql connector at pom.xml

f61b102

Implemented findAll

e0c219d

Changed initDb.sql

c05cc8a

fix mistake with BookDao class name

346f873

Init DataProcessingException

260cd90

Changed throwable type exception from RunTime to DataProccException

58e06a9

Removed id field from constructor

39510da

Add static fabric method

801737f

used a static fabric method instead of a setter + constructor

39326ca

Implemented getRowsCount/clear/create/findById/findAll/update/deleteById

70ae9ad

mateacademy-ai-mentor suggested changes Sep 21, 2024

View reviewed changes

fix some mistakes

2016722

dlvsn requested a review from mateacademy-ai-mentor September 22, 2024 05:21

mateacademy-ai-mentor approved these changes Sep 22, 2024

View reviewed changes

Elena-Bruyako suggested changes Sep 22, 2024

View reviewed changes

dlvsn added 7 commits September 23, 2024 10:31

Deleted methods clear and getRowCount

d0e6c99

Changed field type of id/price from long to Long Wrapper. from int to…

950d728

… BigDecimal

Changed field type in book table

2016a25

added separated methods. Refactored code

e8924fc

Fix some mistakes in initDbSql

426dd56

Task redo

878c6f9

fix mistakes accodring checkstyle

7e7dec3

dlvsn requested a review from Elena-Bruyako September 23, 2024 08:51

Elena-Bruyako suggested changes Sep 23, 2024

View reviewed changes


		bookDao.findById(3L).ifPresent(System.out::println);

		boolean b = bookDao.deleteById(3L);

	long id = resultSet.getLong("id");
	Long id = resultSet.getLong("id");

	id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
	id BIGINT PRIMARY KEY AUTO_INCREMENT,

-            if (storeBook(preparedStatement, book, true)) {
-                throw new RuntimeException("Book not found");
-            }
+            statement.setString(1, book.getTitle());
+            statement.setBigDecimal(2, book.getPrice());
+            statement.setLong(3, book.getId());
+            if (statement.executeUpdate() < 1) {
+                throw new DataProcessingException("Update failed for book with id:" + book.getId());
+            }

	int affectedRow = statement.executeUpdate();
	return statement.executeUpdate() > 0;

HM JDBC #418

Are you sure you want to change the base?

HM JDBC #418

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dlvsn commented Sep 21, 2024

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