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1 using System;
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2 using System.Collections.Generic;
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3 using System.Linq;
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4 using System.Linq.Expressions;
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5
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6 namespace BLToolkit.Data.Linq.Builder
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7 {
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8 using BLToolkit.Linq;
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9 using Data.Sql;
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10
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11 class SubQueryContext : PassThroughContext
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12 {
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13 public readonly IBuildContext SubQuery;
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14
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15 public SubQueryContext(IBuildContext subQuery, SqlQuery sqlQuery, bool addToSql)
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16 : base(subQuery)
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17 {
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18 if (sqlQuery == subQuery.SqlQuery)
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19 throw new ArgumentException("Wrong subQuery argument.", "subQuery");
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20
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21 SubQuery = subQuery;
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22 SubQuery.Parent = this;
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23
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24 SqlQuery = sqlQuery;
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25
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26 if (addToSql)
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27 sqlQuery.From.Table(SubQuery.SqlQuery);
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28 }
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29
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30 public SubQueryContext(IBuildContext subQuery, bool addToSql)
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31 : this(subQuery, new SqlQuery { ParentSql = subQuery.SqlQuery.ParentSql }, addToSql)
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32 {
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33 }
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34
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35 public SubQueryContext(IBuildContext subQuery)
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36 : this(subQuery, true)
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37 {
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38 }
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39
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40 public override SqlQuery SqlQuery { get; set; }
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41 public override IBuildContext Parent { get; set; }
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42
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43 public override void BuildQuery<T>(Query<T> query, ParameterExpression queryParameter)
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44 {
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45 if (Expression.NodeType == ExpressionType.Lambda)
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46 {
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47 var le = (LambdaExpression)Expression;
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48
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49 if (le.Parameters.Count == 1 && null != Expression.Find(
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50 e => e.NodeType == ExpressionType.Call && ((MethodCallExpression)e).IsQueryable()))
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51 {
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52 if (le.Body.NodeType == ExpressionType.New)
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53 {
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54 var ne = (NewExpression)le.Body;
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55 var p = Expression.Parameter(ne.Type, "p");
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56
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57 var seq = new SelectContext(
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58 Parent,
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59 Expression.Lambda(
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60 Expression.New(
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61 ne.Constructor,
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62 ne.Members.Select(m => Expression.MakeMemberAccess(p, m)).ToArray(),
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63 ne.Members),
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64 p),
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65 this);
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66
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67 seq.BuildQuery(query, queryParameter);
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68
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69 return;
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70 }
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71
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72 if (le.Body.NodeType == ExpressionType.MemberInit)
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73 {
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74 var mi = (MemberInitExpression)le.Body;
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75
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76 if (mi.NewExpression.Arguments.Count == 0 && mi.Bindings.All(b => b is MemberAssignment))
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77 {
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78 var p = Expression.Parameter(mi.Type, "p");
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79
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80 var seq = new SelectContext(
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81 Parent,
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82 Expression.Lambda(
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83 Expression.MemberInit(
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84 mi.NewExpression,
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85 mi.Bindings
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86 .OfType<MemberAssignment>()
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87 .Select(ma => Expression.Bind(ma.Member, Expression.MakeMemberAccess(p, ma.Member)))
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88 .ToArray()),
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89 p),
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90 this);
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91
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92 seq.BuildQuery(query, queryParameter);
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93
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94 return;
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95 }
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96 }
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97 }
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98 }
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99
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100 base.BuildQuery(query, queryParameter);
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101 }
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102
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103 public override SqlInfo[] ConvertToSql(Expression expression, int level, ConvertFlags flags)
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104 {
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105 return SubQuery
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106 .ConvertToIndex(expression, level, flags)
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107 .Select(idx => new SqlInfo(idx.Members) { Sql = SubQuery.SqlQuery.Select.Columns[idx.Index] })
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108 .ToArray();
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109 }
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110
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111 // JoinContext has similar logic. Consider to review it.
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112 //
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113 public override SqlInfo[] ConvertToIndex(Expression expression, int level, ConvertFlags flags)
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114 {
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115 return ConvertToSql(expression, level, flags)
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116 .Select(idx =>
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117 {
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118 idx.Query = SqlQuery;
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119 idx.Index = GetIndex((SqlQuery.Column)idx.Sql);
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120
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121 return idx;
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122 })
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123 .ToArray();
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124 }
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125
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126 public override IsExpressionResult IsExpression(Expression expression, int level, RequestFor testFlag)
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127 {
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128 switch (testFlag)
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129 {
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130 case RequestFor.SubQuery : return IsExpressionResult.True;
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131 }
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132
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133 return base.IsExpression(expression, level, testFlag);
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134 }
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135
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136 internal protected readonly Dictionary<ISqlExpression,int> ColumnIndexes = new Dictionary<ISqlExpression,int>();
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137
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138 protected virtual int GetIndex(SqlQuery.Column column)
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139 {
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140 int idx;
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141
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142 if (!ColumnIndexes.TryGetValue(column, out idx))
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143 {
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144 idx = SqlQuery.Select.Add(column);
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145 ColumnIndexes.Add(column, idx);
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146 }
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147
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148 return idx;
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149 }
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150
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151 public override int ConvertToParentIndex(int index, IBuildContext context)
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152 {
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153 var idx = GetIndex(context.SqlQuery.Select.Columns[index]);
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154 return Parent == null ? idx : Parent.ConvertToParentIndex(idx, this);
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155 }
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156
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157 public override void SetAlias(string alias)
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158 {
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159 if (alias.Contains('<'))
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160 return;
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161
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162 if (SqlQuery.From.Tables[0].Alias == null)
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163 SqlQuery.From.Tables[0].Alias = alias;
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164 }
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165
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166 public override ISqlExpression GetSubQuery(IBuildContext context)
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167 {
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168 return null;
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169 }
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170 }
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171 }
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