Question

如何以编程方式将数据输入/插入sqlite数据库。我搜索了类似的问题，但我看到的只是使用cmd或SDK工具来执行此操作。

这是我的主要活动： -

public class MainActivity extends AppCompactActivity {

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_activity);
    SQLiteDatabase db;

    db = openOrCreateDatabase("books.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);

    final String CREATE_BOOKS_TABLE = "CREATE TABLE IF NOT EXISTS book_list ("
            + "id INTEGER primary key AUTOINCREMENT,"
            + "name,"
            + "genre,"
            + "description,"
            + "created_at TIMESTAMP,"")";
    db.execSQL(CREATE_BOOKS_TABLE);

我想做类似的事情：

    insert into books.db values (null, "Wheel of Time.epub", "fantasy", " Its absolutely the best", "2017-02-13 13:11:06");

有什么方法可以做到吗？

Answer 1

您已创建表的列而未指定其类型。它应该是

final String CREATE_BOOKS_TABLE = "CREATE TABLE IF NOT EXISTS book_list ("
        + "id INTEGER primary key AUTOINCREMENT,"
        + "name TEXT,"
        + "genre TEXT,"
        + "description TEXT,"
        + "created_at TIMESTAMP)";

对于Insert，您可以使用：

        String sql =
        "INSERT or replace INTO book_list (name, genre, description, created_at) VALUES('Wheel of Time.epub','fantasy','Its absolutely the best','2017-02-13 13:11:06')" ;       
        db.execSQL(sql);

<强>更新

您可以声明created_at列在插入时默认获取其值，如下所示：

final String CREATE_BOOKS_TABLE = "CREATE TABLE IF NOT EXISTS book_list ("
        + "id INTEGER primary key AUTOINCREMENT,"
        + "name TEXT,"
        + "genre TEXT,"
        + "description TEXT,"
        + "created_at TIMESTAMP not null default current_timestamp)";

然后你在插入时不需要为它设置一个值：

        String sql =
        "INSERT or replace INTO book_list (name, genre, description) VALUES('Wheel of Time.epub','fantasy','Its absolutely the best')" ;       
        db.execSQL(sql);

Answer 2

这是一个非常通用的问题，但我可以想到的最简单的方法，而不进入课程：

将Edittext和按钮拖到活动中。
将按钮附加到Edittext以将数据转换为字符串。
使用上面的insert语句将数据放入数据库。

编辑，此代码是否可以帮助您进行MainActivity：

import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
EditText etName;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final SQLiteDatabase db = this.openOrCreateDatabase("books.db", MODE_PRIVATE, null);// Open or Create Database if none exists

    final String CREATE_BOOKS_TABLE = "CREATE TABLE IF NOT EXISTS book_list ("
            + "id INTEGER primary key AUTOINCREMENT,"
            + "name TEXT,"
            + "genre TEXT,"
            + "description TEXT)";
    db.execSQL(CREATE_BOOKS_TABLE); // Creates the fields for the database

    Button btnData=findViewById(R.id.btnInsertData); // finds the button
    etName=findViewById(R.id.etName); // Our text input box

// Set an OnClickListener for the button so when it's clicked, the code below is triggered  
    btnData.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String nameTxt=etName.getText().toString();
            db.execSQL("INSERT INTO book_list (name, genre, description) VALUES ('"+nameTxt+"', 'fantasy', 'review')"); // Inserts the nameTxt data from the text box into the database, the other fields remain the same 
            Toast.makeText(MainActivity.this, "Data Inserted", Toast.LENGTH_SHORT).show();// Makes a Toast to show the data is inserted
            etName.setText("");// Clears the Textbox
        }
    });
}

}

您的Xml文件：

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<Button
    android:id="@+id/btnInsertData"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Insert"/>

<EditText
    android:id="@+id/etName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="textPersonName"
    android:hint="Name" />
</LinearLayout>

这将为您的数据库创建一个输入字段。它不是干净的代码或最好的方法，但它很简单，并演示了如何获取文本输入并将其放入数据库。

以编程方式手动将数据插入sqlite表

2 个答案: