How to use

alter

method

in

com.englishtown.vertx.cassandra.tablebuilder.TableBuilder

/**
 * Returns a {@link com.datastax.driver.core.BatchStatement} with all the alter statements necessary to modify an existing table.
 * <p>
 * Note: Columns will only be added or modified, not dropped.
 *
 * @param existing the existing table to be modified
 * @param desired  the desired end result
 * @return a set of statements to modify an existing table
 */
public static List<AlterTable> alter(TableMetadata existing, CreateTable desired) {
  List<AlterTable> results = new ArrayList<>();
  for (BuiltTableStatement.Column column : desired.getColumns()) {
    ColumnMetadata columnMetadata = existing.getColumn(column.getName());
    if (columnMetadata == null) {
      results.add(alter(desired.getKeyspace(), desired.getTable()).addColumn(column.getName(), column.getType()));
    } else if (!columnMetadata.getType().toString().equalsIgnoreCase(column.getType())) {
      if (columnMetadata.isStatic()) {
        throw new IllegalArgumentException("A static column cannot have its type modified");
      }
      results.add(alter(desired.getKeyspace(), desired.getTable()).alterColumn(column.getName(), column.getType()));
    }
  }
  return results;
}

/**
 * Returns a {@link com.datastax.driver.core.BatchStatement} with all the alter statements necessary to modify an existing table.
 * <p>
 * Note: Columns will only be added or modified, not dropped.
 *
 * @param existing the existing table to be modified
 * @param desired  the desired end result
 * @return a set of statements to modify an existing table
 */
public static List<AlterTable> alter(AbstractTableMetadata existing, CreateTable desired) {
  List<AlterTable> results = new ArrayList<>();
  for (BuiltTableStatement.Column column : desired.getColumns()) {
    ColumnMetadata columnMetadata = existing.getColumn(column.getName());
    if (columnMetadata == null) {
      results.add(alter(desired.getKeyspace(), desired.getTable()).addColumn(column.getName(), column.getType()));
    } else if (!columnMetadata.getType().toString().equalsIgnoreCase(column.getType())) {
      if (columnMetadata.isStatic()) {
        throw new IllegalArgumentException("A static column cannot have its type modified");
      }
      results.add(alter(desired.getKeyspace(), desired.getTable()).alterColumn(column.getName(), column.getType()));
    }
  }
  return results;
}

/**
 * Returns a {@link com.datastax.driver.core.BatchStatement} with all the alter statements necessary to modify an existing table.
 * <p>
 * Note: Columns will only be added or modified, not dropped.
 *
 * @param existing the existing table to be modified
 * @param desired  the desired end result
 * @return a set of statements to modify an existing table
 */
public static List<AlterTable> alter(AbstractTableMetadata existing, CreateTable desired) {
  List<AlterTable> results = new ArrayList<>();
  for (BuiltTableStatement.Column column : desired.getColumns()) {
    ColumnMetadata columnMetadata = existing.getColumn(column.getName());
    if (columnMetadata == null) {
      results.add(alter(desired.getKeyspace(), desired.getTable()).addColumn(column.getName(), column.getType()));
    } else if (!columnMetadata.getType().toString().equalsIgnoreCase(column.getType())) {
      if (columnMetadata.isStatic()) {
        throw new IllegalArgumentException("A static column cannot have its type modified");
      }
      results.add(alter(desired.getKeyspace(), desired.getTable()).alterColumn(column.getName(), column.getType()));
    }
  }
  return results;
}

@Test
public void testAdd() throws Exception {
  AlterTable alter = TableBuilder.alter("test_keyspace", "test_table")
      .addColumn("col1", "text");
  String cql = alter.getQueryString();
  assertEquals("ALTER TABLE test_keyspace.test_table ADD col1 text", cql);
}

  @Test
  public void testRename() throws Exception {
    AlterTable alter = TableBuilder.alter("test_keyspace", "test_table")
        .renameColumn("col1", "col2");

    String cql = alter.getQueryString();
    assertEquals("ALTER TABLE test_keyspace.test_table RENAME col1 TO col2", cql);
  }
}

@Test
public void testAlter() throws Exception {
  AlterTable alter = TableBuilder.alter("test_keyspace", "test_table")
      .alterColumn("col1", "text");
  String cql = alter.getQueryString();
  assertEquals("ALTER TABLE test_keyspace.test_table ALTER col1 TYPE text", cql);
}

@Test
public void testDrop() throws Exception {
  AlterTable alter = TableBuilder.alter("test_keyspace", "test_table")
      .dropColumn("col1");
  String cql = alter.getQueryString();
  assertEquals("ALTER TABLE test_keyspace.test_table DROP col1", cql);
}

@Test
public void testAlter() throws Exception {
  CreateTable desired = TableBuilder.create("test_keyspace", "test_table")
      .column("col1", "text")
      .column("col2", "bigint")
      .column("col3", "int")
      .column("col4", "text")
      .primaryKey("col1");
  List<AlterTable> statements = TableBuilder.alter(existing, desired);
  assertEquals(3, statements.size());
  assertEquals("ALTER TABLE test_keyspace.test_table ALTER col2 TYPE bigint", statements.get(0).toString());
  assertEquals("ALTER TABLE test_keyspace.test_table ADD col3 int", statements.get(1).toString());
  assertEquals("ALTER TABLE test_keyspace.test_table ADD col4 text", statements.get(2).toString());
}

List<AlterTable> alterStatements = TableBuilder.alter(tableMetadata, createTable);