5 // Copyright (c) 2007-2008 Jiri Moudry, Pascal Craponne
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7 // Permission is hereby granted, free of charge, to any person obtaining a copy
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8 // of this software and associated documentation files (the "Software"), to deal
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9 // in the Software without restriction, including without limitation the rights
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10 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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11 // copies of the Software, and to permit persons to whom the Software is
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12 // furnished to do so, subject to the following conditions:
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14 // The above copyright notice and this permission notice shall be included in
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15 // all copies or substantial portions of the Software.
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17 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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18 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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20 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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21 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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22 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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28 using System.Collections;
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29 using System.Collections.Generic;
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31 using System.Linq.Expressions;
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33 using System.Data.Linq.Sugar;
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35 using DbLinq.Data.Linq.Sugar;
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39 namespace System.Data.Linq.Implementation
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41 namespace DbLinq.Data.Linq.Implementation
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45 /// QueryProvider is used by both DataContext and Table
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46 /// to build queries
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47 /// It is split is two parts (non-generic and generic) for copy reasons
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49 internal abstract class QueryProvider
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52 /// Gets or sets the expression chain.
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54 /// <value>The expression chain.</value>
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55 public ExpressionChain ExpressionChain { get; set; }
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57 /// Gets or sets the type of the table.
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59 /// <value>The type of the table.</value>
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60 public Type TableType { get; set; }
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64 /// <param name="expression">The expression.</param>
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65 /// <returns></returns>
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66 public abstract SelectQuery GetQuery(Expression expression);
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70 /// QueryProvider, generic version
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72 /// <typeparam name="T"></typeparam>
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73 internal class QueryProvider<T> : QueryProvider, IQueryProvider, IQueryable<T>, IOrderedQueryable<T>
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76 /// Holder current datancontext
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78 protected readonly DataContext _dataContext;
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81 /// Initializes a new instance of the <see cref="QueryProvider<T>"/> class.
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83 /// <param name="dataContext">The data context.</param>
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84 public QueryProvider(DataContext dataContext)
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86 _dataContext = dataContext;
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87 TableType = typeof(T);
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88 ExpressionChain = new ExpressionChain();
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92 /// Initializes a new instance of the <see cref="QueryProvider<T>"/> class.
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94 /// <param name="tableType">Type of the table.</param>
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95 /// <param name="dataContext">The data context.</param>
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96 /// <param name="expressionChain">The expression chain.</param>
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97 /// <param name="expression">The expression.</param>
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98 public QueryProvider(Type tableType, DataContext dataContext, ExpressionChain expressionChain, Expression expression)
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100 _dataContext = dataContext;
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101 TableType = tableType;
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102 ExpressionChain = new ExpressionChain(expressionChain, expression);
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106 /// Creates the query.
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108 /// <typeparam name="S"></typeparam>
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109 /// <param name="t">The t.</param>
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110 /// <param name="tableType">Type of the table.</param>
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111 /// <param name="dataContext">The data context.</param>
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112 /// <param name="expressionChain">The expression chain.</param>
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113 /// <param name="expression">The expression.</param>
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114 /// <returns></returns>
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115 protected S CreateQuery<S>(Type t, Type tableType, DataContext dataContext, ExpressionChain expressionChain, Expression expression)
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117 // no way to work differently
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118 var typedQueryProviderType = typeof(QueryProvider<>).MakeGenericType(t);
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119 var queryProvider = (S)Activator.CreateInstance(typedQueryProviderType, tableType, dataContext,
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120 expressionChain, expression);
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121 return queryProvider;
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125 /// Builds the query, given a LINQ expression
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127 /// <param name="expression"></param>
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128 /// <returns></returns>
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129 public IQueryable CreateQuery(Expression expression)
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131 var type = expression.Type;
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132 if (!type.IsGenericType)
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133 throw Error.BadArgument("S0066: Don't know how to handle non-generic type '{0}'", type);
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134 var genericType = type.GetGenericTypeDefinition();
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135 if (genericType == typeof(IQueryable<>) || genericType == typeof(IOrderedQueryable<>))
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136 type = type.GetGenericArguments()[0];
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138 Error.BadArgument("S0068: Don't know how to handle type '{0}'", type);
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139 return CreateQuery<IQueryable>(type, TableType, _dataContext, ExpressionChain, expression);
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143 /// Creates the query.
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145 /// <typeparam name="TElement">The type of the element.</typeparam>
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146 /// <param name="expression">The expression.</param>
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147 /// <returns></returns>
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148 public IQueryable<TElement> CreateQuery<TElement>(Expression expression)
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150 return new QueryProvider<TElement>(TableType, _dataContext, ExpressionChain, expression);
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154 /// Gets the query.
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156 /// <param name="expression">The expression.</param>
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157 /// <returns></returns>
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158 public override SelectQuery GetQuery(Expression expression)
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160 var expressionChain = ExpressionChain;
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161 if (expression != null)
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162 expressionChain = new ExpressionChain(expressionChain, expression);
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163 return _dataContext.QueryBuilder.GetSelectQuery(expressionChain, new QueryContext(_dataContext));
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169 /// <param name="expression"></param>
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170 /// <returns></returns>
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171 public object Execute(Expression expression)
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173 return Execute<object>(expression);
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179 /// <typeparam name="TResult"></typeparam>
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180 /// <param name="expression"></param>
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181 /// <returns></returns>
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182 public TResult Execute<TResult>(Expression expression)
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184 var query = GetQuery(expression);
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185 return _dataContext.QueryRunner.SelectScalar<TResult>(query);
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189 /// Enumerates all query items
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191 /// <returns></returns>
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192 IEnumerator IEnumerable.GetEnumerator()
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194 var enumerator = GetEnumerator();
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199 /// Enumerates all query items
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201 /// <returns></returns>
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202 public IEnumerator<T> GetEnumerator()
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204 var query = GetQuery(null);
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205 return _dataContext.QueryRunner.Select<T>(query).GetEnumerator();
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209 /// Returns this QueryProvider as an exception
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211 public Expression Expression
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213 get { return Expression.Constant(this); }
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216 public Type ElementType
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218 get { return (typeof(T)); }
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221 public IQueryProvider Provider
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223 get { return this; }
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