CreateViewNode.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed 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.
//

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;

using Deveel.Data.Sql.Expressions;
using Deveel.Data.Sql.Statements;

namespace Deveel.Data.Sql.Parser {
    class CreateViewNode : SqlStatementNode {
        public ObjectNameNode ViewName { get; private set; }

        public bool ReplaceIfExists { get; private set; }

        public IEnumerable<string> ColumnNames { get; private set; }

        public SqlQueryExpressionNode QueryExpression { get; private set; }

        protected override ISqlNode OnChildNode(ISqlNode node) {
            if (node.NodeName == "column_list_opt") {
                GetColumnList(node);
            } else if (node.NodeName == "or_replace_opt") {
                if (node.ChildNodes.Any())
                    ReplaceIfExists = true;
            } else if (node is ObjectNameNode) {
                ViewName = (ObjectNameNode) node;
            } else if (node is SqlQueryExpressionNode) {
                QueryExpression = (SqlQueryExpressionNode) node;
            }

            return base.OnChildNode(node);
        }

        private void GetColumnList(ISqlNode node) {
            var columnListNode = node.ChildNodes.FirstOrDefault();
            if (columnListNode == null)
                return;
            
            var columnNames = (columnListNode.ChildNodes.Where(childNode => childNode.NodeName.Equals("column_name"))
                .Select(childNode => childNode.ChildNodes.FirstOrDefault())
                .Where(columnName => columnName != null && columnName is IdentifierNode)
                .Select(columnName => ((IdentifierNode) columnName).Text)).ToList();

            ColumnNames = columnNames.AsEnumerable();
        }

        protected override void BuildStatement(StatementBuilder builder) {
            var queryExpression = (SqlQueryExpression)ExpressionBuilder.Build(QueryExpression);
            var statement = new CreateViewStatement(ViewName.Name, ColumnNames, queryExpression);
            builder.Statements.Add(statement);
        }
    }
}