Examples with Bulk Classes

DB Interface Module User's Guide
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8.2 Examples with Bulk Classes

This section describes examples with bulk classes.

8.2.1 Bulk Read and Writes

Example 7 illustrates the use of RWDBBulkInserter and RWDBBulkReader to insert, read, and print out numeric and date values in the purchase table using RWDBTBuffer<T>.

Example 7: Bulk reads and writes

void insertPurchaseTable(const RWDBDatabase& db) {
  RWDBTable tab = db.table("purchase");
  RWDBBulkInserter ins = tab.bulkInserter(db.connection());
  
  const int dataElements = 10;
  RWDBTBuffer<int> videoID(dataElements);
  RWDBTBuffer<int> supplierID(dataElements);
  RWDBTBuffer<int> purchaseOrderNumber(dataElements);
  RWDBTBuffer<double> pricePerUnit(dataElements);
  RWDBTBuffer<int> quantity(dataElements);
  RWDBTBuffer<RWDateTime> dateBuffer(dataElements);

  // Bind the arrays to the inserter before execution.
  ins << videoID << supplierID << purchaseOrderNumber
      << pricePerUnit << quantity << dateBuffer;

  // Initialize data:
  RWDateTime now(RWDateTime::setCurrentTime);
  for (int i = 0; i < dataElements; i++) {
    videoID[i] = supplierID[i] = purchaseOrderNumber[i] =
      pricePerUnit[i] = quantity[i] = i;
    dateBuffer[i] = now;
  }

  ins.execute();
  return;
}


void readPurchaseTable(const RWDBDatabase& db) {
  RWDBTable tab = db.table("purchase");
  RWDBBulkReader rdr = tab.bulkReader(db.connection());

  const int dataElements = 10;
  RWDBTBuffer<int> videoID(dataElements);
  RWDBTBuffer<int> supplierID(dataElements);
  RWDBTBuffer<int> purchaseOrderNumber(dataElements);
  RWDBTBuffer<double> pricePerUnit(dataElements);
  RWDBTBuffer<int> quantity(dataElements);
  RWDBTBuffer<RWDateTime> dateBuffer(dataElements);

  // Bind the arrays to the reader before execution.
  rdr << videoID << supplierID << purchaseOrderNumber
      << pricePerUnit << quantity << dateBuffer;

// Fetch up to dataElements rows at a time.
  size_t rowsRead= 0;
  while (rowsRead = rdr()) {
    for (size_t i = 0; i < rowsRead; i++) {
      cout << videoID[i] << supplierID[i]
           << purchaseOrderNumber[i]
           << pricePerUnit[i] << quantity[i]
           << dateBuffer[i].asString() << endl;
    }
  }
}

8.2.2 Bulk Classes and RWDBBlob

Example 8 uses classes RWDBBulkInserter and RWDBBulkReader along with RWDBTBuffer<T> to insert and read binary data.

Example 8: Bulk classes and RWDBBlob

#include <rw/rstream.h>
#include <rw/db/db.h>
#include <rw/db/tbuffer.h>

int main()
{
  RWDBDatabase db = RWDBManager::database(
    "ctl8015d.dll", // Access Module type
    "aServer",      // server name
    "aUser",        // user name
    "aPassword",    // password
    "aDB"           // database name
    );

  // get a connection
  RWDBConnection cn = db.connection();

  // create an example table.
  RWDBTable tbl = db.table("binExample");
  if( tbl.exists(cn) ) tbl.drop(cn);
  RWDBSchema sch;
  sch.appendColumn("cBlob", RWDBValue::Blob, 30);
  db.createTable(tbl.name(), sch, cn);

  // scope this section so that the RWDBBulkInserter
  // will release the connection after inserting.
  // This is also needed for Sybase to finish bulk insertion.

  {
    // insert some data
    RWDBTBuffer<RWDBBlob> binBuffer(5);
    RWDBBlob aBlob("hello there\0again", 17);
    for (size_t i = 0; i < 5; ++i)
      binBuffer[i] = aBlob;
    RWDBBulkInserter ins = tbl.bulkInserter(cn);
    ins << binBuffer;
    ins.execute();
  }

  // scoped so that RWDBBulkReader releases the connection
  {
    // now read back the data and print it to the screen
    RWDBBulkReader rdr = tbl.bulkReader(cn);
    RWDBTBuffer<RWDBBlob> binBuffer(5);
    rdr << binBuffer;
    RWDBBlob aBlob;
    size_t rowsRead;
    while (rowsRead = rdr()) {
      for (size_t i = 0; i < rowsRead; ++i) {
        aBlob = binBuffer[i];
        std::cout << "the blob's length is: "
                  << aBlob.length() << std::endl;
        std::cout << "the blob's data is: ";
        unsigned char* ptr = aBlob.data();
        for (size_t j = 0; j < aBlob.length(); ++j, ++ptr) {
          std::cout.put(*ptr);
        }
        std::cout << std::endl;
      }
    }
  }

  tbl.drop(cn);
  return 0;
}

For more information on bulk reading and writing, see the entries in the SourcePro C++ API Reference Guide on RWDBBulkInserter and RWDBBulkReader, and their related class RWDBTBuffer<T>.

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