将 hdfql 中的内存写入数据集

Question

看了文档，还是没有搞清楚如何将内存（变量）中的数据正确写入数据集。例如，随着建筑 CREATE TRUNCATE CHUNKED DATASET dsetint AS INT(UNLIMITED), "INSERT INTO dsetint (-1) VALUES (" << val << ")" 这里没有问题，变量被替换并且记录继续。

例如 "CREATE TRUNCATE CHUNKED DATASET dsetchr AS VARCHAR(UNLIMITED)") char bl[] = "blabal"; "INSERT INTO dsetchr(-1) FROM MEMORY " << HDFql::variableRegister(&bl); 只写零

所以问题出来的例子

在输入端我们有一个字节数组和一个在第一个数组中有数据大小的数组

  uint8_t* ptr ;
    HDFql::execute("CREATE TRUNCATE FILE test.h5");
    HDFql::execute("USE FILE test.h5");

    status = HDFql::execute("CREATE TRUNCATE CHUNKED DATASET inclusion AS UNSIGNED VARTINYINT(UNLIMITED)");

    std::vector<int> s{ 6,12 };
    std::vector<uint8_t> v{0x35,0x34, 0x35, 0x00, 0x00, 0x35,0x36,0x36, 0x36, 0x36, 0x36, 0x36,0x36,0x00, 0x36, 0x00, 0x36, 0x36 };
    ptr = &v[0];

    int number = HDFql::variableRegister(&ptr);
    for (int i = 0; i < s.size();i++)
    {
        scriptst << "INSERT INTO inclusion(-1) VALUES FROM MEMORY " << number << " SIZE " << s[i];
        status = HDFql::execute(scriptst);
        ptr = ptr + s[i];
        HDFql::execute("ALTER DIMENSION Inclusions TO +1");
        scriptst.str(std::string());
        scriptst.clear();
    }
   // my expectation that there will be a record in the file
    // dataset  ->row1      0x35,0x34, 0x35, 0x00, 0x00, 0x35
    // dataset  ->row2      0x36,0x36, 0x36, 0x36, 0x36, 0x36,0x36,0x00, 0x36, 0x00, 0x36, 0x36
    // dataset  ->row3

我想将数据输入到一个文件中，而不会出现数组的缺陷，并且能够随时追加它们。

更新我的实验和阅读文档使我想到了这个例子，但它仍然不能满足我的需要。这里字节数组存储在数据集中，每行 1 个字节。但我仍然想在数据集行上存储一个不同长度的字节数组

status = HDFql::execute("CREATE TRUNCATE FILE test_Titnyint.h5");
    status = HDFql::execute("USE FILE test_Titnyint.h5");
    status = HDFql::execute("CREATE TRUNCATE CHUNKED DATASET inclusion AS UNSIGNED TINYINT(UNLIMITED)");
    std::vector<uint8_t> array{0x35,0x34, 0x00, 0x37, 0x35, 0x35,0x36,0x36, 0x36, 0x36, 0x00, 0x36,0x36,0x36, 0x36, 0x36, 0x36, 0x36 };
     uint8_t* ptr ;
    ptr = &array[0];
    for (int i = 0; i < array.size();i++)
    {
        int number = HDFql::variableRegister(ptr);
        if (i > 0) { status =HDFql::execute("ALTER DIMENSION inclusion TO +1"); }
        scriptst << "INSERT INTO DATASET inclusion(-1) VALUES FROM MEMORY " << number ;
        status = HDFql::execute(scriptst);
        HDFql::variableUnregister(ptr);
        ptr = ptr + 1;
        scriptst.str(std::string());
        scriptst.clear();
    }
     status = HDFql::execute("CLOSE FILE");

备注：向量“s”和“v”应被视为来自外部的输入。

Answer 1

要使用 HDFql 将可变长度数据写入 HDF5 数据集（在您的数据类型 VARTINYINT 的情况下），您需要使用结构类型 HDFQL_VARIABLE_LENGTH 的变量。例如：

HDFQL_VARIABLE_LENGTH my_data;

std::vector<uint8_t> values1 {0x35,0x34, 0x35, 0x00, 0x00, 0x35};

std::vector<uint8_t> values2 {0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x00, 0x36, 0x00, 0x36, 0x36};


HDFql::execute("CREATE TRUNCATE AND USE FILE test.h5");

HDFql::execute("CREATE TRUNCATE CHUNKED DATASET inclusion AS UNSIGNED VARTINYINT(UNLIMITED)");

number = HDFql::variableRegister(&my_data);


my_data.address = values1.data();

my_data.count = values1.size();

script << "INSERT INTO inclusion(-1) VALUES FROM MEMORY " << number;

HDFql::execute(script);


my_data.address = values2.data();

my_data.count = values2.size();

HDFql::execute("ALTER DIMENSION inclusion TO +1");

HDFql::execute(script);

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