Data Ability关系型数据库练习 原创
一、具体场景
主要参照官方示范案例进行的操作练习。最后有完整的跑通的代码供大家参考。练习场景为数据库的交互-后台打印信息。
二、呈现的效果：
三、部分代码说明
“entry > src > main > java > com.xxx.xxx” 选择“File > New > Ability > Empty Data Ability” ，设置“Data Name”为PersonDataAbility并完成创建此时，HUAWEI DevEco Studio将自动生成类PersonDataAbility及相关方法，其继承类Ability（默认实现了数据库的增/删/改/查API方法），部分示例代码如下：
PersonDataAbility中
package com.example.jltfshujuku;
import ohos.aafwk.ability.Ability;
import ohos.aafwk.ability.DataAbilityHelper;
import ohos.aafwk.content.Intent;
import ohos.data.DatabaseHelper;
import ohos.data.dataability.DataAbilityUtils;
import ohos.data.rdb.*;
import ohos.data.resultset.ResultSet;
import ohos.data.dataability.DataAbilityPredicates;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
import ohos.utils.net.Uri;
import ohos.utils.PacMap;
import java.io.FileDescriptor;
public class PersonDataAbility extends Ability {
/*定义Data Ability数据库相关常量*/
private static final String DB_NAME = "persondataability.db";
private static final String DB_TAB_NAME = "person";
private static final String DB_COLUMN_PERSON_ID = "id";
private static final String DB_COLUMN_NAME = "name";
private static final String DB_COLUMN_GENDER = "gender";
private static final String DB_COLUMN_AGE = "age";
private static final int DB_VERSION = 1;
/* 创建关系型数据库*/
private StoreConfig config = StoreConfig.newDefaultConfig(DB_NAME);
private RdbStore rdbStore;
private RdbOpenCallback rdbOpenCallback = new RdbOpenCallback() {
@Override
public void onCreate(RdbStore store) {
store.executeSql("create table if not exists "
+ DB_TAB_NAME + " ("
+ DB_COLUMN_PERSON_ID + " integer primary key, "
+ DB_COLUMN_NAME + " text not null, "
+ DB_COLUMN_GENDER + " text not null, "
+ DB_COLUMN_AGE + " integer)");
}
@Override
public void onUpgrade(RdbStore store, int oldVersion, int newVersion) {
}
};
private static final HiLogLabel LABEL_LOG = new HiLogLabel(3, 0xD001100, "Demo");
@Override
public void onStart(Intent intent) {
super.onStart(intent);
HiLog.info(LABEL_LOG, "PersonDataAbility onStart");
/*初始化数据库连接*/
DatabaseHelper databaseHelper = new DatabaseHelper(this);
rdbStore = databaseHelper.getRdbStore(config, DB_VERSION, rdbOpenCallback, null);
}
/*重写数据库操作方法*/
@Override
public ResultSet query(Uri uri, String[] columns, DataAbilityPredicates predicates) {
/*return null;*/
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, DB_TAB_NAME);
ResultSet resultSet = rdbStore.query(rdbPredicates, columns);
if (resultSet == null) {
HiLog.info(LABEL_LOG, "resultSet is null");
}
return resultSet;
}
@Override
public int insert(Uri uri, ValuesBucket value) {
HiLog.info(LABEL_LOG, "PersonDataAbility insert");
/*return 999;*/
String path = uri.getLastPath();
if (!"person".equals(path)) {
HiLog.info(LABEL_LOG, "DataAbility insert path is not matched");
return -1;
}
ValuesBucket values = new ValuesBucket();
values.putInteger(DB_COLUMN_PERSON_ID, value.getInteger(DB_COLUMN_PERSON_ID));
values.putString(DB_COLUMN_NAME, value.getString(DB_COLUMN_NAME));
values.putString(DB_COLUMN_GENDER, value.getString(DB_COLUMN_GENDER));
values.putInteger(DB_COLUMN_AGE, value.getInteger(DB_COLUMN_AGE));
int index = (int) rdbStore.insert(DB_TAB_NAME, values);
DataAbilityHelper.creator(this, uri).notifyChange(uri);
return index;
}
@Override
public int delete(Uri uri, DataAbilityPredicates predicates) {
/*return 0;*/
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, DB_TAB_NAME);
int index = rdbStore.delete(rdbPredicates);
HiLog.info(LABEL_LOG, "delete: " + index);
DataAbilityHelper.creator(this, uri).notifyChange(uri);
return index;
}
@Override
public int update(Uri uri, ValuesBucket value, DataAbilityPredicates predicates) {
/* return 0;*/
RdbPredicates rdbPredicates = DataAbilityUtils.createRdbPredicates(predicates, DB_TAB_NAME);
int index = rdbStore.update(value, rdbPredicates);
HiLog.info(LABEL_LOG, "update: " + index);
DataAbilityHelper.creator(this, uri).notifyChange(uri);
return index;
}
@Override
public FileDescriptor openFile(Uri uri, String mode) {
return null;
}
@Override
public String[] getFileTypes(Uri uri, String mimeTypeFilter) {
return new String[0];
}
@Override
public PacMap call(String method, String arg, PacMap extras) {
return null;
}
@Override
public String getType(Uri uri) {
return null;
}
}
四、后续计划，数据库的数据用日志的形式在后台打印出来的效果完成后，需要进一步尝试前后端数据的交互。
五、代码地址
https://gitee.com/jltfcloudcn/jump_to/commit/b460666e2997ce284bb5e1ade0801344e045d246
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