/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.drill.exec.planner.sql.handlers;
import java.io.IOException;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.schema.Schema;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.calcite.schema.Table;
import org.apache.calcite.tools.RelConversionException;
import org.apache.calcite.tools.ValidationException;
import org.apache.drill.common.exceptions.UserException;
import org.apache.drill.exec.dotdrill.View;
import org.apache.drill.exec.ops.QueryContext;
import org.apache.drill.exec.physical.PhysicalPlan;
import org.apache.drill.exec.planner.sql.DirectPlan;
import org.apache.drill.exec.planner.sql.SchemaUtilites;
import org.apache.drill.exec.planner.sql.parser.SqlCreateView;
import org.apache.drill.exec.planner.sql.parser.SqlDropView;
import org.apache.drill.exec.store.AbstractSchema;
import org.apache.drill.exec.work.foreman.ForemanSetupException;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.sql.SqlNode;
public abstract class ViewHandler extends DefaultSqlHandler {
private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(ViewHandler.class);
protected QueryContext context;
public ViewHandler(SqlHandlerConfig config) {
super(config);
this.context = config.getContext();
}
/** Handler for Create View DDL command */
public static class CreateView extends ViewHandler {
public CreateView(SqlHandlerConfig config) {
super(config);
}
@Override
public PhysicalPlan getPlan(SqlNode sqlNode) throws ValidationException, RelConversionException, IOException, ForemanSetupException {
SqlCreateView createView = unwrap(sqlNode, SqlCreateView.class);
final String newViewName = createView.getName();
// Disallow temporary tables usage in view definition
config.getConverter().disallowTemporaryTables();
// Store the viewSql as view def SqlNode is modified as part of the resolving the new table definition below.
final String viewSql = createView.getQuery().toString();
final ConvertedRelNode convertedRelNode = validateAndConvert(createView.getQuery());
final RelDataType validatedRowType = convertedRelNode.getValidatedRowType();
final RelNode queryRelNode = convertedRelNode.getConvertedNode();
final RelNode newViewRelNode = SqlHandlerUtil.resolveNewTableRel(true, createView.getFieldNames(), validatedRowType, queryRelNode);
final SchemaPlus defaultSchema = context.getNewDefaultSchema();
final AbstractSchema drillSchema = SchemaUtilites.resolveToMutableDrillSchema(defaultSchema, createView.getSchemaPath());
final View view = new View(newViewName, viewSql, newViewRelNode.getRowType(),
SchemaUtilites.getSchemaPathAsList(defaultSchema));
validateViewCreationPossibility(drillSchema, createView, context);
final boolean replaced = drillSchema.createView(view);
final String summary = String.format("View '%s' %s successfully in '%s' schema",
createView.getName(), replaced ? "replaced" : "created", drillSchema.getFullSchemaName());
return DirectPlan.createDirectPlan(context, true, summary);
}
/**
* Validates if view can be created in indicated schema:
* checks if object (persistent / temporary table) with the same name exists
* or if view with the same name exists but replace flag is not set.
*
* @param drillSchema schema where views will be created
* @param view create view call
* @param context query context
* @throws UserException if views can be created in indicated schema
*/
private void validateViewCreationPossibility(AbstractSchema drillSchema, SqlCreateView view, QueryContext context) {
final String schemaPath = drillSchema.getFullSchemaName();
final String viewName = view.getName();
final Table existingTable = SqlHandlerUtil.getTableFromSchema(drillSchema, viewName);
if ((existingTable != null && existingTable.getJdbcTableType() != Schema.TableType.VIEW) ||
context.getSession().isTemporaryTable(drillSchema, context.getConfig(), viewName)) {
// existing table is not a view
throw UserException
.validationError()
.message("A non-view table with given name [%s] already exists in schema [%s]", viewName, schemaPath)
.build(logger);
}
if ((existingTable != null && existingTable.getJdbcTableType() == Schema.TableType.VIEW) && !view.getReplace()) {
// existing table is a view and create view has no "REPLACE" clause
throw UserException
.validationError()
.message("A view with given name [%s] already exists in schema [%s]", viewName, schemaPath)
.build(logger);
}
}
}
/** Handler for Drop View [If Exists] DDL command. */
public static class DropView extends ViewHandler {
public DropView(SqlHandlerConfig config) {
super(config);
}
@Override
public PhysicalPlan getPlan(SqlNode sqlNode) throws ValidationException, RelConversionException, IOException, ForemanSetupException {
SqlDropView dropView = unwrap(sqlNode, SqlDropView.class);
final String viewName = dropView.getName();
final AbstractSchema drillSchema =
SchemaUtilites.resolveToMutableDrillSchema(context.getNewDefaultSchema(), dropView.getSchemaPath());
final String schemaPath = drillSchema.getFullSchemaName();
final Table viewToDrop = SqlHandlerUtil.getTableFromSchema(drillSchema, viewName);
if (dropView.checkViewExistence()) {
if (viewToDrop == null || viewToDrop.getJdbcTableType() != Schema.TableType.VIEW){
return DirectPlan.createDirectPlan(context, false,
String.format("View [%s] not found in schema [%s].", viewName, schemaPath));
}
} else {
if (viewToDrop != null && viewToDrop.getJdbcTableType() != Schema.TableType.VIEW) {
throw UserException.validationError()
.message("[%s] is not a VIEW in schema [%s]", viewName, schemaPath)
.build(logger);
} else if (viewToDrop == null) {
throw UserException.validationError()
.message("Unknown view [%s] in schema [%s].", viewName, schemaPath)
.build(logger);
}
}
SqlHandlerUtil.dropViewFromSchema(drillSchema, viewName);
return DirectPlan.createDirectPlan(context, true,
String.format("View [%s] deleted successfully from schema [%s].", viewName, schemaPath));
}
}
}