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通过关系型数据库实现数据持久化 (C/C++)

场景介绍​

RelationalStore提供了一套完整的对本地数据库进行管理的机制，对外提供了一系列的增、删、改、查等接口，也可以直接运行用户输入的SQL语句来满足复杂的场景需要。

基本概念​

  • 谓词：数据库中用来代表数据实体的性质、特征或者数据实体之间关系的词项，主要用来定义数据库的操作条件。
  • 结果集：指用户查询之后的结果集合，可以对数据进行访问。结果集提供了灵活的数据访问方式，可以更方便地拿到用户想要的数据。

约束限制​

  • 系统默认日志方式是WAL（Write Ahead Log）模式，系统默认落盘方式是FULL模式。
  • 数据库中连接池的最大数量是4个，用以管理用户的读操作。
  • 为保证数据的准确性，数据库同一时间仅支持一个写操作。
  • 当应用被卸载完成后，设备上的相关数据库文件及临时文件会被自动清除。

接口说明​

详细的接口说明请参考RDB。

接口名称描述
OH_Rdb_ConfigV2 *OH_Rdb_CreateConfig()创建一个OH_Rdb_ConfigV2实例，并返回指向该实例的指针。使用完毕后需要调用OH_Rdb_DestroyConfig释放内存。
int OH_Rdb_SetDatabaseDir(OH_Rdb_ConfigV2 *config, const char *databaseDir)给指定的数据库文件配置OH_Rdb_ConfigV2，设置数据库文件路径。
int OH_Rdb_SetStoreName(OH_Rdb_ConfigV2 *config, const char *storeName)给指定的数据库文件配置OH_Rdb_ConfigV2，设置数据库名称。
int OH_Rdb_SetBundleName(OH_Rdb_ConfigV2 *config, const char *bundleName)给指定的数据库文件配置OH_Rdb_ConfigV2，设置应用包名。
int OH_Rdb_SetModuleName(OH_Rdb_ConfigV2 *config, const char *moduleName)给指定的数据库文件配置OH_Rdb_ConfigV2，设置应用模块名。
int OH_Rdb_SetSecurityLevel(OH_Rdb_ConfigV2 *config, int securityLevel)给指定的数据库文件配置OH_Rdb_ConfigV2，设置数据库安全级别OH_Rdb_SecurityLevel。
int OH_Rdb_SetEncrypted(OH_Rdb_ConfigV2 *config, bool isEncrypted)给指定的数据库文件配置OH_Rdb_ConfigV2，设置数据库是否加密。
int OH_Rdb_SetArea(OH_Rdb_ConfigV2 *config, int area)给指定的数据库文件配置OH_Rdb_ConfigV2，设置数据库安全区域等级Rdb_SecurityArea。
OH_Rdb_Store *OH_Rdb_CreateOrOpen(const OH_Rdb_ConfigV2 *config, int *errCode)使用数据库配置OH_Rdb_ConfigV2，获得一个对应的OH_Rdb_Store实例，用来操作关系型数据库。
OH_Rdb_Execute(OH_Rdb_Store *store, const char *sql)执行包含指定参数但不返回值的SQL语句。
OH_Rdb_Insert(OH_Rdb_Store *store, const char *table, OH_VBucket *valuesBucket)向目标表中插入一行数据。
int OH_Rdb_InsertWithConflictResolution(OH_Rdb_Store *store, const char *table, OH_VBucket *row, Rdb_ConflictResolution resolution, int64_t *rowId)向目标表中插入一行数据，支持配置冲突解决策略。
int OH_Rdb_UpdateWithConflictResolution(OH_Rdb_Store *store, OH_VBucket *row, OH_Predicates *predicates, Rdb_ConflictResolution resolution, int64_t *changes)向目标表中插入一行数据，支持配置冲突解决策略。
OH_Rdb_Update(OH_Rdb_Store *store, OH_VBucket *valuesBucket, OH_Predicates *predicates)根据OH_Predicates的指定实例对象更新数据库中的数据。
OH_Rdb_Delete(OH_Rdb_Store *store, OH_Predicates *predicates)根据OH_Predicates的指定实例对象从数据库中删除数据。
int OH_Predicates_NotLike(OH_Predicates *predicates, const char *field, const char *pattern)设置OH_Predicates以匹配数据类型为字符串且值不类似于指定值的字段。
int OH_Predicates_Glob(OH_Predicates *predicates, const char *field, const char *pattern)设置OH_Predicates以匹配指定字段（数据类型为字符串）且值包含通配符的字段。
int OH_Predicates_NotGlob(OH_Predicates *predicates, const char *field, const char *pattern)设置OH_Predicates以不匹配指定字段（数据类型为字符串）且值包含通配符的字段。
OH_Rdb_Query(OH_Rdb_Store *store, OH_Predicates *predicates, const char *const *columnNames, int length)根据指定条件查询数据库中的数据。
OH_Rdb_DeleteStore(const OH_Rdb_Config *config)删除数据库。
OH_VBucket_PutAsset(OH_VBucket *bucket, const char *field, Rdb_Asset *value)把Rdb_Asset类型的数据放到指定的OH_VBucket对象中。
OH_VBucket_PutAssets(OH_VBucket *bucket, const char *field, Rdb_Asset *value, uint32_t count)把Rdb_Asset数组类型的数据放到指定的OH_VBucket对象中。
OH_Rdb_FindModifyTime(OH_Rdb_Store *store, const char *tableName, const char *columnName, OH_VObject *values)获取数据库指定表中指定列的数据的最后修改时间。
OH_RDB_TransOptions *OH_RdbTrans_CreateOptions(void)创建一个OH_RDB_TransOptions实例，配置事务对象。使用完毕后需要调用OH_RdbTrans_DestroyOptions释放内存。
OH_Cursor *OH_RdbTrans_Query(OH_Rdb_Transaction *trans, const OH_Predicates *predicates, const char *columns[], int len)根据指定的条件查询数据库中的数据。
OH_Data_Values *OH_Values_Create(void)创建OH_Data_Values实例。使用完毕后需要调用OH_Values_Destroy释放内存。
int OH_Data_Asset_SetName(Data_Asset *asset, const char *name)为资产类型数据设置名称。
int OH_Data_Asset_SetUri(Data_Asset *asset, const char *uri)为资产类型数据设置绝对路径。
int OH_Data_Asset_SetPath(Data_Asset *asset, const char *path)为资产类型数据设置应用沙箱里的相对路径。
int OH_Data_Asset_SetCreateTime(Data_Asset *asset, int64_t createTime)为资产类型数据设置创建时间。
int OH_Data_Asset_SetModifyTime(Data_Asset *asset, int64_t modifyTime)为资产类型数据设置最后修改时间。
int OH_Data_Asset_SetSize(Data_Asset *asset, size_t size)为资产类型数据设置占用空间大小。
int OH_Data_Asset_SetStatus(Data_Asset *asset, Data_AssetStatus status)为资产类型数据设置状态码。
int OH_Data_Asset_GetName(Data_Asset *asset, char *name, size_t *length)获取资产类型数据的名称。
int OH_Data_Asset_GetUri(Data_Asset *asset, char *uri, size_t *length)获取资产类型数据的绝对路径。
int OH_Data_Asset_GetPath(Data_Asset *asset, char *path, size_t *length)获取资产类型数据在应用沙箱内的相对路径。
int OH_Data_Asset_GetCreateTime(Data_Asset *asset, int64_t *createTime)获取资产类型数据的创建时间。
int OH_Data_Asset_GetModifyTime(Data_Asset *asset, int64_t *modifyTime)获取资产类型数据的最后修改时间。
int OH_Data_Asset_GetSize(Data_Asset *asset, size_t *size)获取资产类型数据的占用空间大小。
int OH_Data_Asset_GetStatus(Data_Asset *asset, Data_AssetStatus *status)获取资产类型数据的状态码。
Data_Asset *OH_Data_Asset_CreateOne()创建一个资产类型实例。使用完毕后需要调用OH_Data_Asset_DestroyOne释放内存。
int OH_Data_Asset_DestroyOne(Data_Asset *asset)销毁一个资产类型实例并回收内存。
Data_Asset **OH_Data_Asset_CreateMultiple(uint32_t count)创造指定数量的资产类型实例。使用完毕后需要调用OH_Data_Asset_DestroyMultiple释放内存。
int OH_Data_Asset_DestroyMultiple(Data_Asset **assets, uint32_t count)销毁指定数量的资产类型实例并回收内存。
int OH_Rdb_CreateTransaction(OH_Rdb_Store *store, const OH_RDB_TransOptions *options, OH_Rdb_Transaction **trans)创建一个相关的OH_Rdb_Transaction实例，开启事务。
int OH_RdbTransOption_SetType(OH_RDB_TransOptions *options, OH_RDB_TransType type)设置事务对象类型。
int OH_RdbTrans_Insert(OH_Rdb_Transaction *trans, const char *table, const OH_VBucket *row, int64_t *rowId)向目标表中插入一行数据。
int OH_RdbTrans_InsertWithConflictResolution(OH_Rdb_Transaction *trans, const char *table, const OH_VBucket *row, Rdb_ConflictResolution resolution, int64_t *rowId)将一行数据插入到目标表中，支持冲突解决。
int OH_RdbTrans_UpdateWithConflictResolution(OH_Rdb_Transaction *trans, const OH_VBucket *row, const OH_Predicates *predicates, Rdb_ConflictResolution resolution, int64_t *changes)根据指定条件更新数据库中的数据，并支持冲突解决。
int OH_RdbTrans_Delete(OH_Rdb_Transaction *trans, const OH_Predicates *predicates, int64_t *changes)根据OH_Predicates的指定实例对象从数据库中删除数据。
int OH_Value_Destroy(OH_Data_Value *value)销毁OH_Data_Value对象。
int OH_Values_Destroy(OH_Data_Values *values)销毁OH_Values_Destroy对象。
int OH_RdbTrans_Execute(OH_Rdb_Transaction *trans, const char *sql, const OH_Data_Values *args, OH_Data_Value **result)执行包含指定参数的SQL语句。
int OH_RdbTrans_Commit(OH_Rdb_Transaction *trans)提交事务。
int OH_RdbTrans_Rollback(OH_Rdb_Transaction *trans)回滚事务。
int OH_RdbTrans_Destroy(OH_Rdb_Transaction *trans)销毁OH_Rdb_Transaction实例。
int OH_Rdb_Attach(OH_Rdb_Store *store, const OH_Rdb_ConfigV2 *config, const char *attachName, int64_t waitTime, size_t *attachedNumber)将数据库文件附加到当前连接的数据库。
int OH_Rdb_Detach(OH_Rdb_Store *store, const char *attachName, int64_t waitTime, size_t *attachedNumber)从当前数据库中分离指定的数据库。
int OH_Rdb_SetCustomDir(OH_Rdb_ConfigV2 *config, const char *customDir)设置数据库的自定义目录。
int OH_Rdb_SetLocale(OH_Rdb_Store *store, const char *locale)支持不同语言的排序规则。
int OH_Rdb_SetPlugins(OH_Rdb_ConfigV2 *config, const char **plugins, int32_t length)设置具有特定功能（如全文检索）的动态库。

开发步骤​

添加动态链接库

CMakeLists.txt中添加以下lib。

libnative_rdb_ndk.z.so, libhilog_ndk.z.so

头文件

#include <cstdlib>
#include <database/data/data_asset.h>
#include <database/rdb/oh_cursor.h>
#include <database/rdb/oh_predicates.h>
#include <database/rdb/oh_value_object.h>
#include <database/rdb/oh_values_bucket.h>
#include <database/rdb/relational_store.h>
#include <database/rdb/relational_store_error_code.h>
#include <hilog/log.h>

  1. 获取OH_Rdb_Store实例，创建数据库文件。其中dataBaseDir变量为应用沙箱路径，Stage模式下建议使用数据库目录，参考Context的databaseDir属性。FA模式下，由于没有接口获取数据库沙箱路径，可使用应用程序的文件目录，可参考Context的getFilesDir接口。area为数据库文件存放的安全区域，详见contextConstant，开发时需要实现由AreaMode枚举值对Rdb_SecurityArea枚举值的转换。示例代码如下所示：

    // 创建OH_Rdb_ConfigV2对象
    OH_Rdb_ConfigV2 *config = OH_Rdb_CreateConfig();
    // 该路径为应用沙箱路径
    // 数据库文件创建位置将位于沙箱路径 /data/storage/el3/database/rdb/RdbTest.db
    OH_Rdb_SetDatabaseDir(config, "/data/storage/el3/database");
    // 数据库文件存放的安全区域，与databaseDir参数中el路径对应
    OH_Rdb_SetArea(config, RDB_SECURITY_AREA_EL3);
    // 数据库文件名
    OH_Rdb_SetStoreName(config, "RdbTest.db");
    // 应用包名
    OH_Rdb_SetBundleName(config, "com.samples.rdbstore");
    // 应用模块名
    OH_Rdb_SetModuleName(config, "entry");
    // 数据库文件安全等级
    OH_Rdb_SetSecurityLevel(config, OH_Rdb_SecurityLevel::S3);
    // 数据库是否加密
    OH_Rdb_SetEncrypted(config, false);
    // ···

    int errCode = 0;
    // 获取OH_Rdb_Store实例
    OH_Rdb_Store *store_ = OH_Rdb_CreateOrOpen(config, &errCode);
    if (store_ == NULL) {
        OH_LOG_ERROR(LOG_APP, "Create store failed, errCode: %{public}d", errCode);
        OH_Rdb_DestroyConfig(config);
        return;
    }
    if (errCode != OH_Rdb_ErrCode::RDB_OK) {
        OH_LOG_ERROR(LOG_APP, "Create attachStore failed, errCode: %{public}d", errCode);
        OH_Rdb_DestroyConfig(config);
        OH_Rdb_CloseStore(store_);
        return;
    }

    如果需要设置自定义数据库路径，可在上述代码// ...处调用OH_Rdb_SetCustomDir接口设置。如果需要设置为只读模式打开数据库，可在上述代码// ...处可调用OH_Rdb_SetReadOnly接口设置。示例代码如下所示：

    // 可设置自定义数据库路径
    // 数据库文件创建位置将位于沙箱路径 /data/storage/el3/database/a/b/RdbTest.db
    OH_Rdb_SetCustomDir(config, "../a/b");
    // 可设置为只读模式打开数据库
    OH_Rdb_SetReadOnly(config, true);

  2. 获取到OH_Rdb_Store后，调用OH_Rdb_Execute接口创建表，并调用OH_Rdb_Insert接口插入数据。示例代码如下所示：

    char createTableSql[] = "CREATE TABLE IF NOT EXISTS EMPLOYEE (ID INTEGER PRIMARY KEY AUTOINCREMENT, "
        "NAME TEXT NOT NULL, AGE INTEGER, SALARY REAL, CODES BLOB)";
    // 执行建表语句
    OH_Rdb_Execute(store_, createTableSql);
    // 创建键值对实例
    OH_VBucket *valueBucket = OH_Rdb_CreateValuesBucket();
    valueBucket->putText(valueBucket, "NAME", "Lisa");
    valueBucket->putInt64(valueBucket, "AGE", 18); // The value of AGE is 18
    valueBucket->putReal(valueBucket, "SALARY", 100.5); // The value of SALARY is 100.5
    uint8_t arr[] = {1, 2, 3, 4, 5};
    int len = sizeof(arr) / sizeof(arr[0]);
    valueBucket->putBlob(valueBucket, "CODES", arr, len);
    // 插入数据
    int rowId = OH_Rdb_Insert(store_, "EMPLOYEE", valueBucket);

    OH_VBucket *valueBucket2 = OH_Rdb_CreateValuesBucket();
    valueBucket2->putInt64(valueBucket2, "ID", 2); // The value of ID is 2
    valueBucket2->putText(valueBucket2, "NAME", "zhangsan");
    valueBucket2->putInt64(valueBucket2, "AGE", 24); // The value of AGE is 24
    valueBucket2->putReal(valueBucket2, "SALARY", 120.4); // The value of SALARY is 120.4
    int64_t rowId2 = -1;
    // 支持插入数据时配置冲突策略
    int result = OH_Rdb_InsertWithConflictResolution(store_, "EMPLOYEE", valueBucket2,
        Rdb_ConflictResolution::RDB_CONFLICT_REPLACE, &rowId2);
    // 销毁键值对实例
    valueBucket->destroy(valueBucket);
    valueBucket2->destroy(valueBucket2);

    关系型数据库没有显式的flush操作实现持久化，数据插入即保存在持久化文件。

  3. 根据谓词指定的实例对象，对数据进行修改或删除。

    调用OH_Rdb_Update方法修改数据，调用OH_Rdb_Delete方法删除数据。示例代码如下所示：

    // 创建valueBucket对象，用于存储要更新的新数据
    OH_VBucket *valueBucket = OH_Rdb_CreateValuesBucket();
    valueBucket->putText(valueBucket, "NAME", "Rose");
    valueBucket->putInt64(valueBucket, "AGE", 22); // The value of AGE is 22
    valueBucket->putReal(valueBucket, "SALARY", 200.5); // The value of SALARY is 200.5
    uint8_t arr[] = {1, 2, 3, 4, 5};
    int len = sizeof(arr) / sizeof(arr[0]);
    valueBucket->putBlob(valueBucket, "CODES", arr, len);
    // 创建谓词对象，指定更新条件：NAME为"Lisa"且SALARY为100.5
    OH_Predicates *predicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        valueBucket->destroy(valueBucket);
        return;
    }
    OH_VObject *valueObject = OH_Rdb_CreateValueObject();
    const char *name = "Lisa";
    valueObject->putText(valueObject, name);
    predicates->equalTo(predicates, "NAME", valueObject)->andOperate(predicates);
    uint32_t count = 1;
    double salary = 100.5;
    valueObject->putDouble(valueObject, &salary, count);
    predicates->equalTo(predicates, "SALARY", valueObject);
    // 执行更新操作，将符合条件的数据更新为valueBucket中的值
    int changeRows = OH_Rdb_Update(store_, valueBucket, predicates);
    OH_Predicates *predicates2 = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (predicates2 == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        valueObject->destroy(valueObject);
        valueBucket->destroy(valueBucket);
        return;
    }
    OH_VObject *valueObject2 = OH_Rdb_CreateValueObject();
    valueObject2->putText(valueObject2, "Rose");
    predicates2->equalTo(predicates2, "NAME", valueObject2);
    valueBucket->putInt64(valueBucket, "ID", 1); // The value of ID is 1
    valueBucket->putText(valueBucket, "NAME", "zhangsan");
    int64_t changeRows2 = -1;

    // 支持更新数据时配置冲突策略
    int result = OH_Rdb_UpdateWithConflictResolution(store_, valueBucket, predicates2,
        Rdb_ConflictResolution::RDB_CONFLICT_REPLACE, &changeRows2);
    valueObject->destroy(valueObject);
    valueObject2->destroy(valueObject2);
    valueBucket->destroy(valueBucket);
    predicates->destroy(predicates);
    predicates2->destroy(predicates2);
    // 删除数据
    OH_Predicates *predicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    OH_VObject *valueObject = OH_Rdb_CreateValueObject();
    const char *name = "Lisa";
    valueObject->putText(valueObject, name);
    predicates->equalTo(predicates, "NAME", valueObject);
    int deleteRows = OH_Rdb_Delete(store_, predicates);
    valueObject->destroy(valueObject);
    predicates->destroy(predicates);

  4. 根据谓词指定的查询条件查找数据。

    调用OH_Rdb_Query方法查找数据，返回一个OH_Cursor结果集。示例代码如下所示：

    OH_Predicates *predicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    const char *columnNames[] = {"NAME", "AGE"};
    int len = sizeof(columnNames) / sizeof(columnNames[0]);
    OH_Cursor *cursor = OH_Rdb_Query(store_, predicates, columnNames, len);
    if (cursor == NULL) {
        OH_LOG_ERROR(LOG_APP, "Query failed.");
        predicates->destroy(predicates);
        return;
    }
    int columnCount = 0;
    cursor->getColumnCount(cursor, &columnCount);

    // OH_Cursor是一个数据集合的游标，默认指向第-1个记录，有效的数据从0开始
    int64_t age;
    while (cursor->goToNextRow(cursor) == OH_Rdb_ErrCode::RDB_OK) {
        int32_t ageColumnIndex = -1;
        cursor->getColumnIndex(cursor, "AGE", &ageColumnIndex);
        if (ageColumnIndex != -1) {
            cursor->getInt64(cursor, ageColumnIndex, &age);
        }
    }

    // 释放谓词实例
    predicates->destroy(predicates);
    // 释放结果集
    cursor->destroy(cursor);

    配置谓词以LIKE模式或NOT LIKE模式匹配进行数据查询。示例代码如下：

    OH_Predicates *likePredicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (likePredicates == NULL) {
        return;
    }
    OH_VObject *likePattern = OH_Rdb_CreateValueObject();
    likePattern->putText(likePattern, "zh%");
    // 配置谓词以LIKE模式匹配
    likePredicates->like(likePredicates, "NAME", likePattern);

    char *colName[] = { "NAME", "AGE" };
    auto *likeQueryCursor = OH_Rdb_Query(store_, likePredicates, colName, 2); // the length of columnNamesis 2
    if (likeQueryCursor == NULL) {
        likePredicates->destroy(likePredicates);
        likePattern->destroy(likePattern);
        return;
    }
    size_t dataLength = 0;
    int colIndex = -1;
    while (likeQueryCursor->goToNextRow(likeQueryCursor) == OH_Rdb_ErrCode::RDB_OK) {
        likeQueryCursor->getColumnIndex(likeQueryCursor, "NAME", &colIndex);
        likeQueryCursor->getSize(likeQueryCursor, colIndex, &dataLength);
        char *name = (char *)malloc((dataLength + 1) * sizeof(char));
        likeQueryCursor->getText(likeQueryCursor, colIndex, name, dataLength + 1);
        free(name);
    }
    likeQueryCursor->destroy(likeQueryCursor);
    likePredicates->destroy(likePredicates);
    likePattern->destroy(likePattern);

    OH_Predicates *notLikePredicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (notLikePredicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    // 配置谓词以NOT LIKE模式匹配
    OH_Predicates_NotLike(notLikePredicates, "NAME", "zh%");
    auto *notLikeQueryCursor = OH_Rdb_Query(store_, notLikePredicates, colName, 2); // the length ofcolumnNames is 2
    if (notLikeQueryCursor == NULL) {
        notLikePredicates->destroy(notLikePredicates);
        return;
    }
    dataLength = 0;
    colIndex = -1;
    while (notLikeQueryCursor->goToNextRow(notLikeQueryCursor) == OH_Rdb_ErrCode::RDB_OK) {
        notLikeQueryCursor->getColumnIndex(notLikeQueryCursor, "NAME", &colIndex);
        notLikeQueryCursor->getSize(notLikeQueryCursor, colIndex, &dataLength);
        char *name2 = (char *)malloc((dataLength + 1) * sizeof(char));
        notLikeQueryCursor->getText(notLikeQueryCursor, colIndex, name2, dataLength + 1);
        free(name2);
    }

    notLikePredicates->destroy(notLikePredicates);
    notLikeQueryCursor->destroy(notLikeQueryCursor);

    配置谓词以GLOB模式或NOTGLOB模式匹配进行数据查询。示例代码如下：

    OH_Predicates *globPredicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (globPredicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    // 配置谓词以GLOB模式匹配
    OH_Predicates_Glob(globPredicates, "NAME", "zh*");

    char *colName[] = { "NAME", "AGE" };
    auto *globQueryCursor = OH_Rdb_Query(store_, globPredicates, colName, 2); // the length of columnNamesis 2
    if (globQueryCursor == NULL) {
        OH_LOG_ERROR(LOG_APP, "Query failed.");
        globPredicates->destroy(globPredicates);
        return;
    }
    size_t dataLength = 0;
    int colIndex = -1;
    while (globQueryCursor->goToNextRow(globQueryCursor) == OH_Rdb_ErrCode::RDB_OK) {
        globQueryCursor->getColumnIndex(globQueryCursor, "NAME", &colIndex);
        globQueryCursor->getSize(globQueryCursor, colIndex, &dataLength);
        char *name = (char *)malloc((dataLength + 1) * sizeof(char));
        globQueryCursor->getText(globQueryCursor, colIndex, name, dataLength + 1);
        free(name);
    }
    globQueryCursor->destroy(globQueryCursor);
    globPredicates->destroy(globPredicates);

    OH_Predicates *notGlobPredicates = OH_Rdb_CreatePredicates("EMPLOYEE");
    if (notGlobPredicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    // 配置谓词以NOT GLOB模式匹配
    OH_Predicates_NotGlob(notGlobPredicates, "NAME", "zh*");
    auto *notGlobQueryCursor = OH_Rdb_Query(store_, notGlobPredicates, colName, 2); // the length ofcolumnNames is 2
    if (notGlobQueryCursor == NULL) {
        OH_LOG_ERROR(LOG_APP, "Query failed.");
        notGlobPredicates->destroy(notGlobPredicates);
        return;
    }
    dataLength = 0;
    colIndex = -1;
    while (notGlobQueryCursor->goToNextRow(notGlobQueryCursor) == OH_Rdb_ErrCode::RDB_OK) {
        notGlobQueryCursor->getColumnIndex(notGlobQueryCursor, "NAME", &colIndex);
        notGlobQueryCursor->getSize(notGlobQueryCursor, colIndex, &dataLength);
        char *name2 = (char *)malloc((dataLength + 1) * sizeof(char));
        notGlobQueryCursor->getText(notGlobQueryCursor, colIndex, name2, dataLength + 1);
        free(name2);
    }
    notGlobQueryCursor->destroy(notGlobQueryCursor);
    notGlobPredicates->destroy(notGlobPredicates);

    如需指定排序时使用的语言规则，例如zh_CN表示中文，tr_TR表示土耳其语等。可调用OH_Rdb_SetLocale配置相应规则。

    OH_Rdb_SetLocale(store_, "zh_CN");

    如需配置fts（Full-Text Search，即全文搜索引擎）动态库，可使用OH_Rdb_SetPlugins接口进行配置。

    使用约束详见StoreConfig中pluginLibs配置项。

    const char *plugins[] = {
        "/data/storage/el1/bundle/libs/arm64/libtokenizer.so"
    };

    int32_t count = sizeof(plugins) / sizeof(plugins[0]);
    auto setResult = OH_Rdb_SetPlugins(config, plugins, count);

  5. 使用事务对象进行插入、删除或更新数据操作。

    调用OH_RdbTransOption_SetType方法，配置要创建的事务类型，支持配置的事务类型有DEFERRED、IMMEDIATE和EXCLUSIVE，默认为DEFERRED。

    调用OH_Rdb_CreateTransaction方法创建事务对象，使用该事务对象执行相应事务操作。

    OH_RDB_TransOptions *options = OH_RdbTrans_CreateOptions();
    // 配置事务类型
    OH_RdbTransOption_SetType(options, RDB_TRANS_DEFERRED);
    OH_Rdb_Transaction *trans = nullptr;
    // 创建事务对象
    int res = OH_Rdb_CreateTransaction(store_, options, &trans);
    OH_RdbTrans_DestroyOptions(options);
    char transCreateTableSql[] =
        "CREATE TABLE IF NOT EXISTS transaction_table (id INTEGER PRIMARY KEY AUTOINCREMENT, data1 INTEGER, "
        "data2 INTEGER, data3 FLOAT, data4 TEXT, data5 BLOB, data6 ASSET, data7 ASSETS, data8 UNLIMITED INT, "
        "data9 FLOATVECTOR);";

    auto *execResult = OH_Value_Create();

    // 通过事务对象执行创建数据库表SQL语句
    int ret = OH_RdbTrans_Execute(trans, transCreateTableSql, nullptr, &execResult);

    // 创建OH_Data_Values实例
    OH_Data_Values *values = OH_Values_Create();
    ret = OH_Values_PutInt(values, 1); // The value of id is 1
    ret = OH_Values_PutInt(values, 2); // The value of datat2 is 2
    ret = OH_Values_PutReal(values, 1.1); // The value of datat3 is 1.1
    ret = OH_Values_PutText(values, "1"); // The value of datat3 is 1
    unsigned char val[] = {1, 2};
    ret = OH_Values_PutBlob(values, val, sizeof(val) / sizeof(val[0]));

    Data_Asset *asset = OH_Data_Asset_CreateOne();
    ret = OH_Data_Asset_SetName(asset, "name");
    ret = OH_Values_PutAsset(values, asset);
    OH_Data_Asset_DestroyOne(asset);

    Data_Asset **assets = OH_Data_Asset_CreateMultiple(2); // The number of created Data_Assets is 2
    ret = OH_Data_Asset_SetName(assets[0], "name1");
    ret = OH_Data_Asset_SetName(assets[1], "name2");
    ret = OH_Values_PutAssets(values, assets, 2); // The number of Data_ Assets is 2
    ret = OH_Data_Asset_DestroyMultiple(assets, 2); // The number of destroyed Data_Assets is 2

    uint64_t bigInt[] = {1, 2, 3, 4, 5};
    ret = OH_Values_PutUnlimitedInt(values, 0, bigInt, sizeof(bigInt) / sizeof(bigInt[0]));

    const char *insertSql = "INSERT INTO transaction_table "
                            "(data1, data2, data3, data4, data5, data6, data7, data8) VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
    OH_Data_Value *outValue = nullptr;

    // 通过事务对象执行数据插入SQL语句
    ret = OH_RdbTrans_Execute(trans, insertSql, values, &outValue);
    OH_Value_Destroy(outValue);
    OH_Values_Destroy(values);

    OH_VBucket *transValueBucket = OH_Rdb_CreateValuesBucket();
    transValueBucket->putInt64(transValueBucket, "data1", 1); // The value of datat1 is 1
    transValueBucket->putInt64(transValueBucket, "data2", 2); // The value of datat2 is 2
    transValueBucket->putReal(transValueBucket, "data3", 1.1); // The value of datat3 is 1.1
    transValueBucket->putText(transValueBucket, "data4", "1"); // The value of datat4 is 1
    transValueBucket->putBlob(transValueBucket, "data5", val, sizeof(val) / sizeof(val[0]));
    int64_t insertRowId = -1;
    // 通过事务对象执行OH_VBucket数据插入
    int insertRet = OH_RdbTrans_Insert(trans, "transaction_table", transValueBucket, &insertRowId);
    transValueBucket->destroy(transValueBucket);

    OH_VBucket *transValueBucket2 = OH_Rdb_CreateValuesBucket();
    transValueBucket2->putInt64(transValueBucket2, "id", 1); // The value of id is 1
    transValueBucket2->putInt64(transValueBucket2, "data2", 2); // The value of datat2 is 2
    transValueBucket2->putReal(transValueBucket2, "data3", 1.2); // The value of datat3 is 1.2

    int64_t transInsertRow = -1;
    // 支持插入数据时配置冲突策略
    int result = OH_RdbTrans_InsertWithConflictResolution(
        trans, "transaction_table", transValueBucket2, Rdb_ConflictResolution::RDB_CONFLICT_REPLACE, &transInsertRow);

    transValueBucket2->destroy(transValueBucket2);
    OH_VBucket *transValueBucket3 = OH_Rdb_CreateValuesBucket();
    transValueBucket3->putInt64(transValueBucket3, "id", 1); // The value of id is 1
    transValueBucket3->putInt64(transValueBucket3, "data2", 3); // The value of data2 is 3
    transValueBucket3->putReal(transValueBucket3, "data3", 1.2); // The value of data3 is 1.2

    OH_Predicates *transUpdatePredicates = OH_Rdb_CreatePredicates("transaction_table");
    if (transUpdatePredicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        transValueBucket3->destroy(transValueBucket3);
        return;
    }
    auto targetValue = OH_Rdb_CreateValueObject();
    int64_t two = 2;
    targetValue->putInt64(targetValue, &two, 1); // The value of id is 1
    transUpdatePredicates->equalTo(transUpdatePredicates, "data2", targetValue);

    int64_t updateRows = -1;
    // 支持更新数据时配置冲突策略
    OH_RdbTrans_UpdateWithConflictResolution(trans, transValueBucket3, transUpdatePredicates,
                                             Rdb_ConflictResolution::RDB_CONFLICT_REPLACE, &updateRows);
    targetValue->destroy(targetValue);
    transValueBucket3->destroy(transValueBucket3);
    transUpdatePredicates->destroy(transUpdatePredicates);
    OH_Predicates *predicates = OH_Rdb_CreatePredicates("transaction_table");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    const char *columns[] = {"data1", "data2", "data3"};
    // 通过事务对象执行数据查询
    OH_Cursor *cursor = OH_RdbTrans_Query(trans, predicates, columns, sizeof(columns) / sizeof(columns[0]));
    if (cursor == NULL) {
        OH_LOG_ERROR(LOG_APP, "Query failed.");
        predicates->destroy(predicates);
        return;
    }
    int columnCount = 0;
    cursor->getColumnCount(cursor, &columnCount);

    predicates->destroy(predicates);
    cursor->destroy(cursor);
    OH_Predicates *predicates2 = OH_Rdb_CreatePredicates("transaction_table");
    if (predicates2 == NULL) {
       OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
       return;
    }
    OH_VObject *valueObject = OH_Rdb_CreateValueObject();
    if (valueObject == NULL) {
       OH_LOG_ERROR(LOG_APP, "CreateValueObject failed.");
       predicates2->destroy(predicates2);
       return;
    }
    valueObject->putText(valueObject, "1"); // Change the text value of the object to 1
    predicates2->equalTo(predicates2, "data4", valueObject);
    int64_t changes = -1;
    // 通过事务对象执行数据删除
    int deleteRet = OH_RdbTrans_Delete(trans, predicates2, &changes);
    predicates2->destroy(predicates2);
    valueObject->destroy(valueObject);
    // 提交事务
    OH_RdbTrans_Commit(trans);
    // 销毁事务
    OH_RdbTrans_Destroy(trans);
    OH_RDB_TransOptions *options2 = OH_RdbTrans_CreateOptions();
    OH_RdbTransOption_SetType(options2, RDB_TRANS_DEFERRED);
    OH_Rdb_Transaction *trans2 = nullptr;
    int transCreateRet = OH_Rdb_CreateTransaction(store_, options2, &trans2);
    OH_RdbTrans_DestroyOptions(options2);

    // 回滚事务
    OH_RdbTrans_Rollback(trans2);
    OH_RdbTrans_Destroy(trans2);

  6. 附加数据库。

    调用OH_Rdb_Attach将一个数据库文件附加到当前数据库中，以便在SQL语句中可以直接访问附加数据库中的数据。

    此API不支持附加加密数据库。

    调用attach接口后，数据库切换为非WAL模式，性能会存在一定的劣化。切换模式需要确保所有的OH_Cursor都已经销毁，所有的写操作已经结束，否则会报错14800015。

    attach不能并发调用，可能出现未响应情况，报错14800015，需要重试。

    当不再使用附加数据时，可调用OH_Rdb_Detach分离附加数据库。

    char attachStoreTableCreateSql[] = "CREATE TABLE IF NOT EXISTS EMPLOYEE (ID INTEGER PRIMARY KEY AUTOINCREMENT, "
        "NAME TEXT NOT NULL, AGE INTEGER, SALARY REAL, CODES BLOB)";
    OH_Rdb_ConfigV2 *attachDbConfig = OH_Rdb_CreateConfig();
    if (attachDbConfig == NULL) {
        OH_LOG_ERROR(LOG_APP, "Create store config failed.");
        return;
    }
    OH_Rdb_SetModuleName(attachDbConfig, "entry");
    OH_Rdb_SetDatabaseDir(attachDbConfig, "/data/storage/el3/database");
    OH_Rdb_SetArea(attachDbConfig, RDB_SECURITY_AREA_EL3);
    OH_Rdb_SetStoreName(attachDbConfig, "RdbAttach.db");
    OH_Rdb_SetSecurityLevel(attachDbConfig, OH_Rdb_SecurityLevel::S3);
    OH_Rdb_SetBundleName(attachDbConfig, "com.example.nativedemo");

    int errCode1 = 0;
    // 创建附加示例数据库 RdbAttach.db
    OH_Rdb_Store *attachStore = OH_Rdb_CreateOrOpen(attachDbConfig, &errCode1);

    if (attachStore == NULL) {
        OH_LOG_ERROR(LOG_APP, "Create attachStore failed, errCode: %{public}d", errCode1);
        OH_Rdb_DestroyConfig(attachDbConfig);
        return;
    }

    if (errCode1 != OH_Rdb_ErrCode::RDB_OK) {
        OH_LOG_ERROR(LOG_APP, "Create attachStore failed, errCode: %{public}d", errCode1);
        OH_Rdb_DestroyConfig(attachDbConfig);
        OH_Rdb_CloseStore(attachStore);
        return;
    }
    errCode1 = OH_Rdb_Execute(attachStore, attachStoreTableCreateSql);
    if (errCode1 != OH_Rdb_ErrCode::RDB_OK) {
        OH_LOG_ERROR(LOG_APP, "Create table failed, errCode: %{public}d", errCode1);
        OH_Rdb_DestroyConfig(attachDbConfig);
        OH_Rdb_CloseStore(attachStore);
        return;
    }
    OH_VBucket *valueBucket = OH_Rdb_CreateValuesBucket();
    valueBucket->putText(valueBucket, "NAME", "Lisa");
    valueBucket->putInt64(valueBucket, "AGE", 18); // The value of AGE is 18
    valueBucket->putReal(valueBucket, "SALARY", 100.5); // The value of AGE is 100.5
    uint8_t arr[] = {1, 2, 3, 4, 5};
    int len = sizeof(arr) / sizeof(arr[0]);
    valueBucket->putBlob(valueBucket, "CODES", arr, len);
    int rowId = OH_Rdb_Insert(attachStore, "EMPLOYEE", valueBucket);
    OH_LOG_INFO(LOG_APP, "Insert data result: %{public}d", rowId);
    valueBucket->destroy(valueBucket);
    OH_Rdb_CloseStore(attachStore);

    // 附加数据库
    size_t attachedNumber = 0;
    // The maximum waiting time allowed for attaching databases is 10
    errCode = OH_Rdb_Attach(store_, attachDbConfig, "attach", 10, &attachedNumber);
    OH_Rdb_DestroyConfig(attachDbConfig);
    if (errCode != OH_Rdb_ErrCode::RDB_OK) {
        OH_LOG_ERROR(LOG_APP, "Attach store failed, errCode: %{public}d", errCode);
        return;
    }
    OH_Predicates *predicates = OH_Rdb_CreatePredicates("attach.EMPLOYEE");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        // The maximum waiting time allowed for detaching databases is 10
        errCode = OH_Rdb_Detach(store_, "attach", 10, &attachedNumber);
        OH_LOG_INFO(LOG_APP, "Detach result: %{public}d", errCode);
        return;
    }
    char *colName[] = {};
    int len = sizeof(colName) / sizeof(colName[0]);
    OH_Cursor *cursor = OH_Rdb_Query(store_, predicates, colName, len);
    if (cursor == NULL) {
        OH_LOG_ERROR(LOG_APP, "Query failed.");
        // The maximum waiting time allowed for detaching databases is 10
        errCode = OH_Rdb_Detach(store_, "attach", 10, &attachedNumber);
        OH_LOG_INFO(LOG_APP, "Detach result: %{public}d", errCode);
        predicates->destroy(predicates);
        return;
    }
    int rowCount = -1;
    errCode = cursor->getRowCount(cursor, &rowCount);
    if (errCode != OH_Rdb_ErrCode::RDB_OK) {
        OH_LOG_ERROR(LOG_APP, "Get row count failed, errCode: %{public}d", errCode);
    } else {
        OH_LOG_INFO(LOG_APP, "Query success, row count: %{public}d", rowCount);
    }
    cursor->destroy(cursor);
    predicates->destroy(predicates);
    // 分离数据库
    // The maximum waiting time allowed for detaching databases is 10
    errCode = OH_Rdb_Detach(store_, "attach", 10, &attachedNumber);
    OH_LOG_INFO(LOG_APP, "Detach result: %{public}d", errCode);

  7. 向数据库表中插入资产类型数据。

    // 列的属性为单个资产类型时，sql语句中应指定为asset，多个资产类型应指定为assets。
    char createAssetTableSql[] = "CREATE TABLE IF NOT EXISTS asset_table (id INTEGER PRIMARY KEY AUTOINCREMENT,"
        "data1 ASSET, data2 ASSETS );";
    const char *table = "asset_table";
    int errCode = OH_Rdb_Execute(store_, createAssetTableSql);
    OH_VBucket *valueBucket = OH_Rdb_CreateValuesBucket();
    Data_Asset *asset = OH_Data_Asset_CreateOne();
    OH_Data_Asset_SetName(asset, "name0");
    OH_Data_Asset_SetUri(asset, "uri0");
    OH_Data_Asset_SetPath(asset, "path0");
    OH_Data_Asset_SetCreateTime(asset, 1); // Set the creation time of Data_Asset to 1
    OH_Data_Asset_SetModifyTime(asset, 1); // Set the modify time of Data_Asset to 1
    OH_Data_Asset_SetSize(asset, 1); // Set the size of the Data_Asset to 1
    OH_Data_Asset_SetStatus(asset, Data_AssetStatus::ASSET_NORMAL);
    errCode = OH_VBucket_PutAsset(valueBucket, "data1", asset);

    Data_Asset **assets = OH_Data_Asset_CreateMultiple(2);

    OH_Data_Asset_SetName(assets[0], "name0");
    OH_Data_Asset_SetUri(assets[0], "uri0");
    OH_Data_Asset_SetPath(assets[0], "path0");
    OH_Data_Asset_SetCreateTime(assets[0], 1); // Set the creation time of Data_Asset to 1
    OH_Data_Asset_SetModifyTime(assets[0], 1); // Set the modify time of Data_Asset to 1
    OH_Data_Asset_SetSize(assets[0], 1); // Set the size of the Data_Asset to 1
    OH_Data_Asset_SetStatus(assets[0], Data_AssetStatus::ASSET_NORMAL);

    OH_Data_Asset_SetName(assets[1], "name1");
    OH_Data_Asset_SetUri(assets[1], "uri1");
    OH_Data_Asset_SetPath(assets[1], "path1");
    OH_Data_Asset_SetCreateTime(assets[1], 1); // Set the creation time of Data_Asset to 1
    OH_Data_Asset_SetModifyTime(assets[1], 1); // Set the modify time of Data_Asset to 1
    OH_Data_Asset_SetSize(assets[1], 1); // Set the size of the Data_Asset to 1
    OH_Data_Asset_SetStatus(assets[1], Data_AssetStatus::ASSET_NORMAL);

    uint32_t assetsCount = 2;
    errCode = OH_VBucket_PutAssets(valueBucket, "data2", assets, assetsCount);
    int rowID = OH_Rdb_Insert(store_, table, valueBucket);
    // 释放Data_Asset*和Data_Asset**
    OH_Data_Asset_DestroyMultiple(assets, assetsCount);
    OH_Data_Asset_DestroyOne(asset);
    valueBucket->destroy(valueBucket);

  8. 从结果集中读取资产类型数据。

    OH_Predicates *predicates = OH_Rdb_CreatePredicates("asset_table");
    if (predicates == NULL) {
        OH_LOG_ERROR(LOG_APP, "CreatePredicates failed.");
        return;
    }
    OH_Cursor *cursor = OH_Rdb_Query(store_, predicates, NULL, 0);
    if (cursor == NULL) {
        predicates->destroy(predicates);
    } else {
        cursor->goToNextRow(cursor);
        
        uint32_t assetCount = 0;
        // assetCount作为出参获取该列资产类型数据的数量
        int errCode = cursor->getAssets(cursor, 2, nullptr, &assetCount); // Column index is 2
        Data_Asset **assets = OH_Data_Asset_CreateMultiple(assetCount);
        errCode = cursor->getAssets(cursor, 2, assets, &assetCount); // Column index is 2
        // The number of Data_Assets is 2
        if (assetCount < 2) {
            predicates->destroy(predicates);
            cursor->destroy(cursor);
        } else {
            Data_Asset *asset = assets[1];
            char name[10] = "";
            size_t nameLength = 10;
            errCode = OH_Data_Asset_GetName(asset, name, &nameLength);
            
            char uri[10] = "";
            size_t uriLength = 10;
            errCode = OH_Data_Asset_GetUri(asset, uri, &uriLength);
            
            char path[10] = "";
            size_t pathLength = 10;
            errCode = OH_Data_Asset_GetPath(asset, path, &pathLength);
            
            int64_t createTime = 0;
            errCode = OH_Data_Asset_GetCreateTime(asset, &createTime);
            
            int64_t modifyTime = 0;
            errCode = OH_Data_Asset_GetModifyTime(asset, &modifyTime);
            
            size_t size = 0;
            errCode = OH_Data_Asset_GetSize(asset, &size);
            
            Data_AssetStatus status = Data_AssetStatus::ASSET_NULL;
            errCode = OH_Data_Asset_GetStatus(asset, &status);
            
            predicates->destroy(predicates);
            OH_Data_Asset_DestroyMultiple(assets, assetCount);
            cursor->destroy(cursor);
        }
    }

  9. 查询数据的最后修改时间。调用OH_Rdb_FindModifyTime查询指定表中指定列的数据的最后修改时间，该接口返回一个有两列数据的OH_Cursor对象，第一列为传入的主键/RowId，第二列为最后修改时间。示例代码如下所示：

    constexpr uint32_t  tableCount = 1;
    const char *table[tableCount];
    table[0] = "EMPLOYEE";
    Rdb_DistributedConfig distributedConfig{ .version = 1, .isAutoSync = true };
    // 设置分布式表
    OH_Rdb_SetDistributedTables(store_, table, tableCount, RDB_DISTRIBUTED_CLOUD, &distributedConfig);
    // 查询数据的最后修改时间
    OH_VObject *values = OH_Rdb_CreateValueObject();
    int64_t keys[] = { 1 };
    values->putInt64(values, keys, 1); // The value of keys is 1
    OH_Cursor *cursor = OH_Rdb_FindModifyTime(store_, "EMPLOYEE", "ROWID", values);
    if (cursor == NULL) {
        return;
    }
    while (cursor->goToNextRow(cursor) == OH_Rdb_ErrCode::RDB_OK) {
        int64_t rowId;
        cursor->getInt64(cursor, 1, &rowId); // 1 is the column index
    }

  10. 删除数据库。调用OH_Rdb_DeleteStoreV2方法，删除数据库及数据库相关文件。示例代码如下：

    // 释放数据库实例
    OH_Rdb_CloseStore(store_);
    // 删除数据库文件
    OH_Rdb_DeleteStoreV2(config);