Litepal is an open-source Android database framework. It uses the object relational mapping (ORM) mode to encapsulate some database functions that we usually use.

Add dependent file

compile 'org.litepal.android:core:1.6.1'

Object relational mapping (ORM): the programming language we use is the object-oriented language, and the database we use is the relational database.

1. Create a new assets directory under main, and a new literal.xml under assets

<?xml version="1.0" encoding="utf-8" ?>
<litepal>
    <dbname values="BookStore" />
    <version value="1" />
    <list>
        <mapping class="com.example.app2.fileStorage.Book" />
    </list>
</litepal>

Here, we use the < mapping > tag to declare the mapping class model we want to configure. Be sure to use the full class name. No matter how many model classes need to be mapped, use the same method in the < list > tag.

public class Book {

    private int id;
    private String author;
    private double price;
    private int page;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

1. Create database

public void onLitePalClick(View view) {
        Connector.getDatabase();
    }

2. Upgrade database

Add press column to Book

 private String press;

public String getPress() {
        return press;
    }

    public void setPress(String press) {
        this.press = press;
    }

New Category class

public class Category {

    private int id;
    private String categoryName;
    private int categoryCode;

    public void setId(int id) {
        this.id = id;
    }

    public void setCategoryName(String categoryName) {
        this.categoryName = categoryName;
    }

    public void setCategoryCode(int categoryCode) {
        this.categoryCode = categoryCode;
    }
}

Modify literal.xml

<?xml version="1.0" encoding="utf-8" ?>
<litepal>
    <dbname values="BookStore" />
    <version value="2" />
    <list>
        <mapping class="com.example.app2.fileStorage.Book" />
        <mapping class="com.example.app2.fileStorage.Category" />
    </list>
</litepal>

3. Add data

Let Book inherit the DataSupport class

public class Book extends DataSupport {

}

 public void onLitePalInsertClick(View view) {
        Book book = new Book();
        book.setName("four");
        book.setAuthor("dave");
        book.setPage(300);
        book.setPrice(34.26);
        book.setPress("UnKnow");
        book.save();
    }

Add the data through the book.save() method.

3. Update data

For literal, whether an object has been stored is determined according to the model.isSaved() method. A return of true indicates that it has been stored and a return of false indicates that it has not been stored.

public void onLitePalUpdateClick(View view) {
        Book book = new Book();
        book.setName("five");
        book.setAuthor("cheery");
        book.setPage(367);
        book.setPrice(85.36);
        book.setPress("UnKnow");
        book.save();
        book.setPrice(573);
        book.save();
    }

perhaps

public void onLitePalUpdateClick(View view) {
        Book book = new Book();
        book.setPrice(85.36);
        book.setPress("UnKnow");
        book.updateAll("name = ? and author = ?", "five", "cheery");
    }

4. Delete data

 public void onLitePalDeleteClick(View view) {
        DataSupport.deleteAll(Book.class, "price < 55");
    }

5. Query data

 public void onLitePalQueryClick(View view) {
        List<Book> list = DataSupport.findAll(Book.class);
        for (Book book : list) {
            Log.d("TAG", "book name is" + book.getName());
            Log.d("TAG", "book author is" + book.getAuthor());
            Log.d("TAG", "book pages is" + book.getPage());
            Log.d("TAG", "book price is" + book.getPrice());
            Log.d("TAG", "book price is" + book.getPress());
        }
    }