示例#1
0
  /** Unit test for TupleDesc.combine() */
  @Test
  public void combine() {
    TupleDesc td1, td2, td3;

    td1 = Utility.getTupleDesc(1, "td1");
    td2 = Utility.getTupleDesc(2, "td2");

    // test td1.combine(td2)
    td3 = TupleDesc.merge(td1, td2);
    assertEquals(3, td3.numFields());
    assertEquals(3 * Type.INT_TYPE.getLen(), td3.getSize());
    for (int i = 0; i < 3; ++i) assertEquals(Type.INT_TYPE, td3.getFieldType(i));
    assertEquals(combinedStringArrays(td1, td2, td3), true);

    // test td2.combine(td1)
    td3 = TupleDesc.merge(td2, td1);
    assertEquals(3, td3.numFields());
    assertEquals(3 * Type.INT_TYPE.getLen(), td3.getSize());
    for (int i = 0; i < 3; ++i) assertEquals(Type.INT_TYPE, td3.getFieldType(i));
    assertEquals(combinedStringArrays(td2, td1, td3), true);

    // test td2.combine(td2)
    td3 = TupleDesc.merge(td2, td2);
    assertEquals(4, td3.numFields());
    assertEquals(4 * Type.INT_TYPE.getLen(), td3.getSize());
    for (int i = 0; i < 4; ++i) assertEquals(Type.INT_TYPE, td3.getFieldType(i));
    assertEquals(combinedStringArrays(td2, td2, td3), true);
  }
示例#2
0
  /** Suck up tuples from the source file. */
  private Tuple readNextTuple(DataInputStream dis, int slotId) throws NoSuchElementException {
    // if associated bit is not set, read forward to the next tuple, and
    // return null.
    if (!getSlot(slotId)) {
      for (int i = 0; i < td.getSize(); i++) {
        try {
          dis.readByte();
        } catch (IOException e) {
          throw new NoSuchElementException("error reading empty tuple");
        }
      }
      return null;
    }

    // read fields in the tuple
    Tuple t = new Tuple(td);
    RecordID rid = new RecordID(pid, slotId);
    t.setRecordID(rid);
    try {
      for (int j = 0; j < td.numFields(); j++) {
        Field f = td.getType(j).parse(dis);
        t.setField(j, f);
      }
    } catch (java.text.ParseException e) {
      // e.printStackTrace();
      throw new NoSuchElementException("parsing error!");
    }

    return t;
  }
示例#3
0
  /** Unit test for TupleDesc.numFields() */
  @Test
  public void numFields() {
    int[] lengths = new int[] {1, 2, 1000};

    for (int len : lengths) {
      TupleDesc td = Utility.getTupleDesc(len);
      assertEquals(len, td.numFields());
    }
  }
示例#4
0
  /**
   * Generates a byte array representing the contents of this page. Used to serialize this page to
   * disk.
   *
   * <p>The invariant here is that it should be possible to pass the byte array generated by
   * getPageData to the HeapPage constructor and have it produce an identical HeapPage object.
   *
   * @see #HeapPage
   * @return A byte array correspond to the bytes of this page.
   */
  public byte[] getPageData() {
    // int len = header.length*4 + BufferPool.PAGE_SIZE;
    int len = BufferPool.PAGE_SIZE;
    ByteArrayOutputStream baos = new ByteArrayOutputStream(len);
    DataOutputStream dos = new DataOutputStream(baos);

    // create the header of the page
    try {
      dos.write(header.getHeader());
    } catch (IOException e) {
      // this really shouldn't happen
      e.printStackTrace();
    }

    // create the tuples
    for (int i = 0; i < numSlots; i++) {

      // empty slot
      if (!getSlot(i)) {
        for (int j = 0; j < td.getSize(); j++) {
          try {
            dos.writeByte(0);
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
        continue;
      }

      // non-empty slot
      for (int j = 0; j < td.numFields(); j++) {
        Field f = tuples[i].getField(j);
        try {
          f.serialize(dos);
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }

    // padding
    int zerolen = BufferPool.PAGE_SIZE - numSlots * td.getSize() - header.length();
    byte[] zeroes = new byte[zerolen];
    try {
      dos.write(zeroes, 0, zerolen);
    } catch (IOException e) {
      e.printStackTrace();
    }

    try {
      dos.flush();
    } catch (IOException e) {
      e.printStackTrace();
    }

    return baos.toByteArray();
  }
示例#5
0
 private void createAliasedTd() {
   Catalog gc = Database.getCatalog();
   TupleDesc old_td = gc.getTupleDesc(tableid);
   String[] newFieldAr = new String[old_td.numFields()];
   Type[] typeAr = new Type[old_td.numFields()];
   String field = null;
   for (int i = 0; i < newFieldAr.length; i++) {
     field = old_td.getFieldName(i);
     if (alias == null) {
       alias = "null";
     } else if (field == null) {
       field = "null";
     }
     newFieldAr[i] = alias + "." + field;
     typeAr[i] = old_td.getFieldType(i);
   }
   td = new TupleDesc(typeAr, newFieldAr);
 }
示例#6
0
 /**
  * Returns the TupleDesc with field names from the underlying HeapFile, prefixed with the
  * tableAlias string from the constructor. This prefix becomes useful when joining tables
  * containing a field(s) with the same name.
  *
  * @return the TupleDesc with field names from the underlying HeapFile, prefixed with the
  *     tableAlias string from the constructor.
  */
 public TupleDesc getTupleDesc() {
   TupleDesc tup = Database.getCatalog().getTupleDesc(id);
   int length = tup.numFields();
   String[] field = new String[length];
   Type[] types = new Type[length];
   for (int i = 0; i < length; i++) {
     types[i] = tup.getFieldType(i);
     field[i] = alias + "." + tup.getFieldName(i);
   }
   return new TupleDesc(types, field);
 }
示例#7
0
  /**
   * Create a new TableStats object, that keeps track of statistics on each column of a table
   *
   * @param tableid The table over which to compute statistics
   * @param ioCostPerPage The cost per page of IO. This doesn't differentiate between
   *     sequential-scan IO and disk seeks.
   */
  public TableStats(int tableid, int ioCostPerPage) {
    // For this function, we use the DbFile for the table in question,
    // then scan through its tuples and calculate the values that you
    // to build the histograms.

    // TODO: Fill out the rest of the constructor.
    // Feel free to change anything already written, it's only a guideline

    this.ioCostPerPage = ioCostPerPage;
    DbFile file = Database.getCatalog().getDbFile(tableid);
    tupleDesc = file.getTupleDesc();
    numPages = ((HeapFile) file).numPages();
    numTuples = 0;

    int numFields = tupleDesc.numFields();

    // TODO: what goes here?
    statistics = new ArrayList<Object>();

    for (int i = 0; i < numFields; i++) {
      if (Type.INT_TYPE.equals(tupleDesc.getFieldType(i))) {
        statistics.add(new IntStatistics(NUM_HIST_BINS));
      } else {
        statistics.add(new StringHistogram(NUM_HIST_BINS));
      }
    }

    final DbFileIterator iter = file.iterator(null);
    try {
      iter.open();

      while (iter.hasNext()) {
        Tuple t = iter.next();
        numTuples++;

        // TODO: and here?
        for (int i = 0; i < numFields; i++) {
          if (Type.INT_TYPE.equals(tupleDesc.getFieldType(i))) {
            ((IntStatistics) statistics.get(i)).addValue(((IntField) t.getField(i)).getValue());
          } else {
            ((StringHistogram) statistics.get(i))
                .addValue(((StringField) t.getField(i)).getValue());
          }
        }
      }
      iter.close();
    } catch (DbException e) {
      e.printStackTrace();
    } catch (TransactionAbortedException e) {
      e.printStackTrace();
    }
  }
示例#8
0
  /** Ensures that combined's field names = td1's field names + td2's field names */
  private boolean combinedStringArrays(TupleDesc td1, TupleDesc td2, TupleDesc combined) {
    for (int i = 0; i < td1.numFields(); i++) {
      if (!(((td1.getFieldName(i) == null) && (combined.getFieldName(i) == null))
          || td1.getFieldName(i).equals(combined.getFieldName(i)))) {
        return false;
      }
    }

    for (int i = td1.numFields(); i < td1.numFields() + td2.numFields(); i++) {
      if (!(((td2.getFieldName(i - td1.numFields()) == null) && (combined.getFieldName(i) == null))
          || td2.getFieldName(i - td1.numFields()).equals(combined.getFieldName(i)))) {
        return false;
      }
    }

    return true;
  }
示例#9
0
  /**
   * Returns the TupleDesc with field names from the underlying HeapFile, prefixed with the
   * tableAlias string from the constructor. This prefix becomes useful when joining tables
   * containing a field(s) with the same name.
   *
   * @return the TupleDesc with field names from the underlying HeapFile, prefixed with the
   *     tableAlias string from the constructor.
   */
  public TupleDesc getTupleDesc() {
    // some code goes here
    TupleDesc td = Database.getCatalog().getTupleDesc(tableid);
    Iterator<TDItem> tdIter = td.iterator();
    int size = td.numFields();
    Type[] typeAr = new Type[size];
    String[] fieldAr = new String[size];

    String aliasString = this.tableAlias;

    TDItem item;
    Type fieldType;
    String fieldName;
    int count = 0;

    if (aliasString == null) {
      aliasString = "null";
    }
    //      for (int i = 0; i < size; i++){
    //    	item = tdIter.next();
    //    	fieldType = item.fieldType;
    //    	fieldName = item.fieldName;

    while (tdIter.hasNext()) {
      item = tdIter.next();
      fieldType = item.fieldType;
      fieldName = item.fieldName;
      if (fieldName == null) {
        fieldName = "null";
      }
      typeAr[count] = fieldType;
      fieldAr[count] = aliasString + "." + fieldName; // "null.null case may occur"
      count++;
    }
    return new TupleDesc(typeAr, fieldAr);
  }