| // 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.impala.analysis; |
| |
| import org.apache.impala.authorization.Privilege; |
| import org.apache.impala.common.AnalysisException; |
| import org.apache.impala.thrift.TDescribeDbParams; |
| import org.apache.impala.thrift.TDescribeOutputStyle; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.base.Strings; |
| |
| /** |
| * Represents a DESCRIBE DATABASE statement which returns metadata on |
| * a specified database: |
| * Syntax: DESCRIBE DATABASE [FORMATTED|EXTENDED] <db> |
| * |
| * If FORMATTED|EXTENDED is not specified, the statement only returns the given |
| * database's location and comment. |
| * If FORMATTED|EXTENDED is specified, extended metadata on the database is returned. |
| * This metadata includes info about the database's parameters, owner info |
| * and privileges. |
| */ |
| public class DescribeDbStmt extends StatementBase { |
| private final TDescribeOutputStyle outputStyle_; |
| private final String dbName_; |
| |
| public DescribeDbStmt(String dbName, TDescribeOutputStyle outputStyle) { |
| Preconditions.checkState(!Strings.isNullOrEmpty(dbName), "Invalid database name"); |
| dbName_ = dbName; |
| outputStyle_ = outputStyle; |
| } |
| |
| @Override |
| public String toSql(ToSqlOptions options) { |
| StringBuilder sb = new StringBuilder("DESCRIBE DATABASE "); |
| if (outputStyle_ != TDescribeOutputStyle.MINIMAL) { |
| sb.append(outputStyle_.toString() + " "); |
| } |
| return sb.toString() + dbName_; |
| } |
| |
| public String getDb() { return dbName_; } |
| |
| @Override |
| public void analyze(Analyzer analyzer) throws AnalysisException { |
| analyzer.getDb(dbName_, Privilege.VIEW_METADATA); |
| } |
| |
| public TDescribeDbParams toThrift() { |
| TDescribeDbParams params = new TDescribeDbParams(); |
| params.setDb(dbName_); |
| params.setOutput_style(outputStyle_); |
| return params; |
| } |
| } |