【鸿蒙】关系型数据库在真机的使用

2022-11-30 131

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简介： 1.组件在真机上演示，创建数据库和打开数据库，只用button组件就行了

1.组件

在真机上演示，创建数据库和打开数据库，只用button组件就行了

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">
    <Button
        ohos:id="$+id:crate_db_button"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text="创建数据库"
        ohos:text_size="20vp"
        ohos:text_color="#ffff"
        ohos:background_element="$graphic:button_bg"
        ohos:top_padding="8vp"
        ohos:left_padding="50vp"
        ohos:right_padding="50vp"
        ohos:layout_alignment="horizontal_center"
        ohos:top_margin="30vp"
        ohos:text_weight="700"/>
    <Button
        ohos:id="$+id:open_db_button"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text_size="20vp"
        ohos:text="打开数据库"
        ohos:text_color="#ffff"
        ohos:background_element="$graphic:button_bg"
        ohos:top_padding="8vp"
        ohos:left_padding="50vp"
        ohos:right_padding="50vp"
        ohos:layout_alignment="horizontal_center"
        ohos:top_margin="30vp"
        ohos:text_weight="700"/>
</DirectionalLayout>

按钮样式

<?xml version="1.0" encoding="UTF-8" ?>
<shape xmlns:ohos="http://schemas.huawei.com/res/ohos"
       ohos:shape="rectangle">
    <corners ohos:radius="15"/>
    <solid
        ohos:color="blue"/>
</shape>

2.

创建和启动数据库的代码分开来写，先初始化按钮

然后将前面文章所写创建和打开的代码分别放入到两个按钮当中，

创建数据库

cdb = (Button) findComponentById(ResourceTable.Id_crate_db_button);
        cdb.setClickedListener(c->{
            // 创建数据库
            StoreConfig.Builder builder = new StoreConfig.Builder();
            String keystr = "123456";
            builder.setName("stan.db")
                    .setSyncMode(null)
                    .setJournalMode(StoreConfig.JournalMode.MODE_WAL)
                    .setStorageMode(StoreConfig.StorageMode.MODE_DISK)
                    .setReadOnly(false)
                    .setDatabaseFileType(DatabaseFileType.NORMAL)
                    //加密
                    .setEncryptKey(keystr.getBytes());
            StoreConfig config = builder.build();
            //创建数据库的实质循环，重要的核心类
            DatabaseHelper helper=new DatabaseHelper(MainAbilitySlice.this);
            //进一步通过helper，获取数据库对象
            //传入四个参数
            RdbStore rdbStore = helper.getRdbStore(config, 1, Callback, null);
            ValuesBucket valuesBucket = new ValuesBucket();
            valuesBucket.putInteger("id",1);
            valuesBucket.putString("name","zhangsan");
            valuesBucket.putInteger("age", 28);
            valuesBucket.putDouble("salary", 8000.5);
            long test = rdbStore.insert("test", valuesBucket);
            System.out.println("========test"+test);
            valuesBucket.putInteger("id",2);
            valuesBucket.putString("name","wangwu");
            valuesBucket.putInteger("age", 28);
            valuesBucket.putDouble("salary", 80001.5);
            long test1 = rdbStore.insert("test", valuesBucket);
            System.out.println("========test"+test1);
        });

读取数据

odb = (Button) findComponentById(ResourceTable.Id_open_db_button);
        odb.setClickedListener(component -> {
            // 打开已经存在的数据库
            StoreConfig.Builder builder = new StoreConfig.Builder();
            String keystr = "123456";
            builder.setName("stan.db")
                    .setSyncMode(null)
                    .setJournalMode(StoreConfig.JournalMode.MODE_WAL)
                    .setStorageMode(StoreConfig.StorageMode.MODE_DISK)
                    .setReadOnly(false)
                    .setDatabaseFileType(DatabaseFileType.NORMAL)
                    //加密
                    .setEncryptKey(keystr.getBytes());
            StoreConfig config = builder.build();
            DatabaseHelper helper=new DatabaseHelper(MainAbilitySlice.this);
            //进一步通过helper，获取数据库对象
            //传入四个参数
            RdbStore rdbStore = helper.getRdbStore(config, 1, openCallback, null);
            ResultSet resultSet = rdbStore.
                    querySql("select id,name,age,salary from test where age=? order by salary desc", new String[]{"28"});
            for (int i=0;i<resultSet.getRowCount();i++){
                resultSet.goToRow(i);
                System.out.println("+++++++++id"+resultSet.getInt(resultSet.getColumnIndexForName("id")));
                System.out.println("+++++++++name"+resultSet.getString(resultSet.getColumnIndexForName("name")));
                System.out.println("+++++++++age"+resultSet.getInt(resultSet.getColumnIndexForName("age")));
                System.out.println("+++++++++salary"+resultSet.getDouble(resultSet.getColumnIndexForName("salary")));
            }
        });