UpdateStatement.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 Deveel.Data.Serialization;
using Deveel.Data.Sql.Expressions;
using Deveel.Data.Sql.Query;
using Deveel.Data.Sql.Tables;

namespace Deveel.Data.Sql.Statements {
    public sealed class UpdateStatement : SqlStatement, IPreparableStatement {
        public UpdateStatement(string tableName, SqlExpression wherExpression, IEnumerable<SqlColumnAssignment> assignments) {
            if (wherExpression == null)
                throw new ArgumentNullException("wherExpression");
            if (assignments == null)
                throw new ArgumentNullException("assignments");
            if (String.IsNullOrEmpty(tableName))
                throw new ArgumentNullException("tableName");

            TableName = tableName;
            WherExpression = wherExpression;
            Assignments = assignments;
        }

        public string TableName { get; private set; }

        public SqlExpression WherExpression { get; private set; }

        public int Limit { get; set; }

        public IEnumerable<SqlColumnAssignment> Assignments { get; private set; }

        IStatement IPreparableStatement.Prepare(IRequest context) {
            var tableName = context.Query.ResolveTableName(TableName);
            if (!context.Query.TableExists(tableName))
                throw new ObjectNotFoundException(tableName);

            var queryExpression = new SqlQueryExpression(new[]{SelectColumn.Glob("*") });
            queryExpression.FromClause.AddTable(tableName.FullName);
            queryExpression.WhereExpression = WherExpression;

            var queryFrom = QueryExpressionFrom.Create(context, queryExpression);
            var queryPlan = context.Query.Context.QueryPlanner().PlanQuery(new QueryInfo(context, queryExpression));

            var columns = new List<SqlAssignExpression>();
            foreach (var assignment in Assignments) {
                var columnName = ObjectName.Parse(assignment.ColumnName);

                var refName = queryFrom.ResolveReference(columnName);
                var expression = assignment.Expression.Prepare(queryFrom.ExpressionPreparer);

                var assign = SqlExpression.Assign(SqlExpression.Reference(refName), expression);
                columns.Add(assign);
            }

            return new Prepared(tableName, queryPlan, columns.ToArray(), Limit);
        }

        #region Prepared

        [Serializable]
        sealed class Prepared : SqlStatement {
            internal Prepared(ObjectName tableName, IQueryPlanNode queryPlan, SqlAssignExpression[] columns, int limit) {
                TableName = tableName;
                QueryPlan = queryPlan;
                Columns = columns;
                Limit = limit;
            }

            private Prepared(ObjectData data) {
                TableName = data.GetValue<ObjectName>("TableName");
                QueryPlan = data.GetValue<IQueryPlanNode>("QueryPlan");
                Columns = data.GetValue<SqlAssignExpression[]>("Columns");
                Limit = data.GetInt32("Limit");
            }

            public ObjectName TableName { get; private set; }

            public IQueryPlanNode QueryPlan { get; private set; }

            public SqlAssignExpression[] Columns { get; private set; }

            public int Limit { get; private set; }

            protected override void ExecuteStatement(ExecutionContext context) {
                var updateCount = context.Request.Query.UpdateTable(TableName, QueryPlan, Columns, Limit);
                context.SetResult(updateCount);
            }

            protected override void GetData(SerializeData data) {
                data.SetValue("TableName", TableName);
                data.SetValue("QueryPlan", QueryPlan);
                data.SetValue("Columns", Columns);
                data.SetValue("Limit", Limit);
            }
        }

        #endregion
    }
}