Java DataContext.executeQuery方法代码示例

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public SimpleDictionary loadIntoMemory(final DatastoreConnection datastoreConnection) {
    final DataContext dataContext = datastoreConnection.getDataContext();
    final Column column = getColumn(datastoreConnection);

    final Query query = dataContext.query().from(column.getTable()).select(column).toQuery();
    if (datastoreConnection.getDatastore().getPerformanceCharacteristics().isQueryOptimizationPreferred()) {
        query.getSelectClause().setDistinct(true);
    }

    final Set<String> values = new HashSet<>();

    try (DataSet dataSet = dataContext.executeQuery(query)) {
        while (dataSet.next()) {
            final Object value = dataSet.getRow().getValue(0);
            if (value != null) {
                values.add(value.toString());
            }
        }
    }

    return new SimpleDictionary(getName(), values);
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public DataSetWindow(final Query query, final DataContext dataContext, final int pageSize,
        final WindowContext windowContext) {
    super(windowContext);
    _table = new DCTable();
    _query = query;
    _pageSize = pageSize;
    _title = "DataSet: " + _query.toSql();
    _tableModelCallable = () -> {
        final DataSet dataSet = dataContext.executeQuery(_query);
        return new DataSetTableModel(dataSet);
    };
    _previousPageButton = WidgetFactory.createDefaultButton("Previous page", IconUtils.ACTION_BACK);
    _previousPageButton.setEnabled(false);
    _nextPageButton = WidgetFactory.createDefaultButton("Next page", IconUtils.ACTION_FORWARD);
    _nextPageButton.setHorizontalTextPosition(SwingConstants.LEFT);
    _nextPageButton.setEnabled(false);
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
private DataSet getPreviewData(final String filename) {
    if (!isPreviewDataAvailable()) {
        logger.info("Not displaying preview table because isPreviewDataAvailable() returned false");
        return null;
    }

    final D datastore = getPreviewDatastore(filename);
    try (DatastoreConnection con = datastore.openConnection()) {
        final DataContext dc = con.getDataContext();
        final Table table = getPreviewTable(dc);

        List<Column> columns = table.getColumns();
        if (columns.size() > getPreviewColumns()) {
            // include max 10 columns
            columns = columns.stream().limit(getPreviewColumns()).collect(Collectors.toList());
        }
        final Query q = dc.query().from(table).select(columns).toQuery();
        q.setMaxRows(7);

        return dc.executeQuery(q);
    }
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testFullScenario() throws Exception {
    final OutputWriterScenarioHelper scenarioHelper = new OutputWriterScenarioHelper();

    final String filename = "target/test-output/csv-file1.txt";
    final OutputWriter writer = CsvOutputWriterFactory.getWriter(filename, scenarioHelper.getColumns());

    scenarioHelper.writeExampleData(writer);
    writer.close();

    final DataContext dc = DataContextFactory.createCsvDataContext(new File(filename));
    final Table table = dc.getDefaultSchema().getTable(0);
    final Query q = dc.query().from(table).select(table.getColumns()).toQuery();
    final DataSet dataSet = dc.executeQuery(q);

    scenarioHelper.performAssertions(dataSet, false);
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
@Override
public Collection<String> getValues() {
    try (final DatastoreConnection con = _datastore.openConnection()) {
        final DataContext dataContext = con.getDataContext();

        final Query q = dataContext.query().from(_column.getTable()).select(_column).toQuery();
        q.selectDistinct();

        try (final DataSet dataSet = dataContext.executeQuery(q)) {
            final List<String> values = new ArrayList<String>();
            while (dataSet.next()) {
                final Row row = dataSet.getRow();
                
                Object value = row.getValue(0);
                if (value != null) {
                    value = value.toString();
                }
                values.add((String) value);
            }
            return values;
        }
    }
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testConfigurationWithoutHeader() throws Exception {
    File file = copyOf("src/test/resources/xls_people.xls");
    DataContext dc = new ExcelDataContext(file, new ExcelConfiguration(ExcelConfiguration.NO_COLUMN_NAME_LINE,
            true, true));
    Table table = dc.getDefaultSchema().getTables().get(0);

    String[] columnNames = table.getColumnNames().toArray(new String[0]);
    assertEquals("[A, B, C, D]", Arrays.toString(columnNames));

    Query q = dc.query().from(table).select(table.getColumnByName("A")).toQuery();
    assertEquals("SELECT xls_people.A FROM testConfigurationWithoutHeader-xls_people.xls.xls_people", q.toSql());

    DataSet dataSet = dc.executeQuery(q);
    assertTrue(dataSet.next());
    assertEquals("id", dataSet.getRow().getValue(0));
    for (int i = 1; i <= 9; i++) {
        assertTrue(dataSet.next());
        assertEquals(i + "", dataSet.getRow().getValue(0));
    }

    assertFalse(dataSet.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testConfigurationNonDefaultColumnNameLineNumber() throws Exception {
    File file = copyOf("src/test/resources/xls_people.xls");
    DataContext dc = new ExcelDataContext(file, new ExcelConfiguration(2, true, true));
    Table table = dc.getDefaultSchema().getTables().get(0);

    String[] columnNames = table.getColumnNames().toArray(new String[0]);
    assertEquals("[1, mike, male, 18]", Arrays.toString(columnNames));

    Query q = dc.query().from(table).select(table.getColumnByName("1")).toQuery();
    assertEquals("SELECT xls_people.1 FROM testConfigurationNonDefaultColumnNameLineNumber-xls_people.xls.xls_people", q.toSql());

    DataSet dataSet = dc.executeQuery(q);
    assertTrue(dataSet.next());
    assertEquals("2", dataSet.getRow().getValue(0));
    for (int i = 3; i <= 9; i++) {
        assertTrue(dataSet.next());
        assertEquals(i + "", dataSet.getRow().getValue(0));
    }
    assertFalse(dataSet.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testMissingValues() throws Exception {
    File file = copyOf("src/test/resources/xls_missing_values.xls");
    DataContext dc = new ExcelDataContext(file);
    Schema schema = dc.getDefaultSchema();
    assertEquals(2, schema.getTableCount());

    Table table = schema.getTables().get(0);
    assertEquals("[Column[name=a,columnNumber=0,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=b,columnNumber=1,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=c,columnNumber=2,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=d,columnNumber=3,type=VARCHAR,nullable=true,nativeType=null,columnSize=null]]",
            Arrays.toString(table.getColumns().toArray()));

    Query q = new Query().select(table.getColumns()).from(table);
    DataSet ds = dc.executeQuery(q);
    assertTrue(ds.next());
    assertEquals("[1, 2, 3, null]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[5, null, 7, 8]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[9, 10, 11, 12]", Arrays.toString(ds.getRow().getValues()));
    assertFalse(ds.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testMissingColumnHeader() throws Exception {
    File file = copyOf("src/test/resources/xls_missing_column_header.xls");
    DataContext dc = new ExcelDataContext(file);
    Schema schema = dc.getDefaultSchema();
    assertEquals(2, schema.getTableCount());

    Table table = schema.getTables().get(0);
    assertEquals("[Column[name=a,columnNumber=0,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=b,columnNumber=1,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=A,columnNumber=2,type=VARCHAR,nullable=true,nativeType=null,columnSize=null], "
            + "Column[name=d,columnNumber=3,type=VARCHAR,nullable=true,nativeType=null,columnSize=null]]",
            Arrays.toString(table.getColumns().toArray()));

    Query q = new Query().select(table.getColumns()).from(table);
    DataSet ds = dc.executeQuery(q);
    assertTrue(ds.next());
    assertEquals("[1, 2, 3, 4]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[5, 6, 7, 8]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[9, 10, 11, 12]", Arrays.toString(ds.getRow().getValues()));
    assertFalse(ds.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testAlternativeConnectionString() throws Exception {
    if (!isConfigured()) {
        return;
    }

    DataContext dc = new JdbcDataContext(getConnection(), TableType.DEFAULT_TABLE_TYPES, "sakila");
    final Schema sakila = dc.getSchemaByName("sakila");
    assertNotNull(sakila);

    Table table = sakila.getTableByName("film");
    Query q = new Query().from(table).select(table.getColumns());
    DataSet data = dc.executeQuery(q);
    TableModel tableModel = new DataSetTableModel(data);
    assertEquals(13, tableModel.getColumnCount());
    assertEquals(1000, tableModel.getRowCount());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testVaryingValueLengthsCorrect() throws Exception {
    DataContext dc = new FixedWidthDataContext(new File("src/test/resources/example_simple2.txt"),
            new FixedWidthConfiguration(new int[] { 1, 8, 7 }));
    Table table = dc.getDefaultSchema().getTables().get(0);
    assertEquals("[i, greeting, greeter]", Arrays.toString(table.getColumnNames().toArray()));

    assertEquals(1, table.getColumnByName("i").getColumnSize().intValue());
    assertEquals(8, table.getColumnByName("greeting").getColumnSize().intValue());
    assertEquals(7, table.getColumnByName("greeter").getColumnSize().intValue());

    Query q = dc.query().from(table).select(table.getColumns()).toQuery();
    DataSet ds = dc.executeQuery(q);

    assertTrue(ds.next());
    assertEquals("[1, hello, world]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[2, hi, there]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[3, howdy, partner]", Arrays.toString(ds.getRow().getValues()));
    assertFalse(ds.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testVaryingValueLengthsTooShortLengthErrorTolerant() throws Exception {
    DataContext dc = new FixedWidthDataContext(new File("src/test/resources/example_simple2.txt"),
            new FixedWidthConfiguration(FixedWidthConfiguration.DEFAULT_COLUMN_NAME_LINE, "UTF8", new int[] { 1, 5,
                    7 }, false));

    Table table = dc.getDefaultSchema().getTables().get(0);
    assertEquals("[i, greet, inggree]", Arrays.toString(table.getColumnNames().toArray()));

    Query q = dc.query().from(table).select(table.getColumns()).toQuery();
    DataSet ds = dc.executeQuery(q);

    assertTrue(ds.next());
    assertEquals("[1, hello, worl]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[2, hi, ther]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[3, howdy, part]", Arrays.toString(ds.getRow().getValues()));
    assertFalse(ds.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testVaryingValueLengthsTooLongLengthErrorTolerant() throws Exception {
    DataContext dc = new FixedWidthDataContext(new File("src/test/resources/example_simple2.txt"),
            new FixedWidthConfiguration(FixedWidthConfiguration.DEFAULT_COLUMN_NAME_LINE, "UTF8", new int[] { 1, 8,
                    9 }, false));

    Table table = dc.getDefaultSchema().getTables().get(0);
    assertEquals("[i, greeting, greeter]", Arrays.toString(table.getColumnNames().toArray()));

    Query q = dc.query().from(table).select(table.getColumns()).toQuery();
    DataSet ds = dc.executeQuery(q);

    assertTrue(ds.next());
    assertEquals("[1, hello, world]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[2, hi, there]", Arrays.toString(ds.getRow().getValues()));
    assertTrue(ds.next());
    assertEquals("[3, howdy, partner]", Arrays.toString(ds.getRow().getValues()));
    assertFalse(ds.next());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
@SuppressWarnings("resource")
public void testNonConvertedQuery() throws Exception {
    MockUpdateableDataContext source = new MockUpdateableDataContext();
    Column fooColumn = source.getColumnByQualifiedLabel("schema.table.foo");
    assertNotNull(fooColumn);

    Map<Column, TypeConverter<?, ?>> converters = new HashMap<Column, TypeConverter<?, ?>>();
    converters.put(fooColumn, new StringToIntegerConverter());
    DataContext converted = Converters.addTypeConverter(source, fooColumn, new StringToIntegerConverter());

    // only select "bar" which is not converted
    Table table = converted.getDefaultSchema().getTableByName("table");
    Query query = converted.query().from(table).select("bar").toQuery();
    assertEquals("SELECT table.bar FROM schema.table", query.toSql());

    DataSet ds = converted.executeQuery(query);
    while (ds instanceof WrappingDataSet) {
        ds = ((WrappingDataSet) ds).getWrappedDataSet();
    }
    ds.close();
    assertEquals(InMemoryDataSet.class, ds.getClass());
}
 

import org.apache.metamodel.DataContext; //导入方法依赖的package包/类
public void testApproximatedCountHugeFile() throws Exception {
    DataContext dc = new CsvDataContext(getHugeFile());

    Table table = dc.getDefaultSchema().getTables().get(0);
    Query q = dc.query().from(table).selectCount().toQuery();
    SelectItem selectItem = q.getSelectClause().getItem(0);
    selectItem.setFunctionApproximationAllowed(true);

    DataSet ds = dc.executeQuery(q);
    assertTrue(ds.next());
    Object[] values = ds.getRow().getValues();
    assertEquals(1, values.length);
    assertEquals(3332, ((Long) ds.getRow().getValue(selectItem)).intValue());
    assertEquals(3332, ((Long) values[0]).intValue());
    assertFalse(ds.next());
}