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comparison Source/Data/Sql/SqlExpression.cs @ 0:f990fcb411a9

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Копия текущей версии из github
author cin
date Thu, 27 Mar 2014 21:46:09 +0400
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-1:000000000000 0:f990fcb411a9
1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5
6 namespace BLToolkit.Data.Sql
7 {
8 public class SqlExpression : ISqlExpression
9 {
10 public SqlExpression(Type systemType, string expr, int precedence, params ISqlExpression[] parameters)
11 {
12 if (parameters == null) throw new ArgumentNullException("parameters");
13
14 foreach (var value in parameters)
15 if (value == null) throw new ArgumentNullException("parameters");
16
17 SystemType = systemType;
18 Expr = expr;
19 Precedence = precedence;
20 Parameters = parameters;
21 }
22
23 public SqlExpression(string expr, int precedence, params ISqlExpression[] parameters)
24 : this(null, expr, precedence, parameters)
25 {
26 }
27
28 public SqlExpression(Type systemType, string expr, params ISqlExpression[] parameters)
29 : this(systemType, expr, Sql.Precedence.Unknown, parameters)
30 {
31 }
32
33 public SqlExpression(string expr, params ISqlExpression[] parameters)
34 : this(null, expr, Sql.Precedence.Unknown, parameters)
35 {
36 }
37
38 public Type SystemType { get; private set; }
39 public string Expr { get; private set; }
40
41 public int Precedence { get; private set; }
42 public ISqlExpression[] Parameters { get; private set; }
43
44 #region Overrides
45
46 #if OVERRIDETOSTRING
47
48 public override string ToString()
49 {
50 return ((IQueryElement)this).ToString(new StringBuilder(), new Dictionary<IQueryElement,IQueryElement>()).ToString();
51 }
52
53 #endif
54
55 #endregion
56
57 #region ISqlExpressionWalkable Members
58
59 [Obsolete]
60 ISqlExpression ISqlExpressionWalkable.Walk(bool skipColumns, Func<ISqlExpression,ISqlExpression> func)
61 {
62 for (var i = 0; i < Parameters.Length; i++)
63 Parameters[i] = Parameters[i].Walk(skipColumns, func);
64
65 return func(this);
66 }
67
68 #endregion
69
70 #region IEquatable<ISqlExpression> Members
71
72 bool IEquatable<ISqlExpression>.Equals(ISqlExpression other)
73 {
74 return Equals(other, DefaultComparer);
75 }
76
77 #endregion
78
79 #region ISqlExpression Members
80
81 public bool CanBeNull()
82 {
83 foreach (var value in Parameters)
84 if (value.CanBeNull())
85 return true;
86
87 return false;
88 }
89
90 public static Func<ISqlExpression,ISqlExpression,bool> DefaultComparer = (x, y) => true;
91
92 public bool Equals(ISqlExpression other, Func<ISqlExpression,ISqlExpression,bool> comparer)
93 {
94 if (this == other)
95 return true;
96
97 var expr = other as SqlExpression;
98
99 if (expr == null || SystemType != expr.SystemType || Expr != expr.Expr || Parameters.Length != expr.Parameters.Length)
100 return false;
101
102 for (var i = 0; i < Parameters.Length; i++)
103 if (!Parameters[i].Equals(expr.Parameters[i], comparer))
104 return false;
105
106 return comparer(this, other);
107 }
108
109 #endregion
110
111 #region ICloneableElement Members
112
113 public ICloneableElement Clone(Dictionary<ICloneableElement, ICloneableElement> objectTree, Predicate<ICloneableElement> doClone)
114 {
115 if (!doClone(this))
116 return this;
117
118 ICloneableElement clone;
119
120 if (!objectTree.TryGetValue(this, out clone))
121 {
122 objectTree.Add(this, clone = new SqlExpression(
123 SystemType,
124 Expr,
125 Precedence,
126 Parameters.Select(e => (ISqlExpression)e.Clone(objectTree, doClone)).ToArray()));
127 }
128
129 return clone;
130 }
131
132 #endregion
133
134 #region IQueryElement Members
135
136 public QueryElementType ElementType { get { return QueryElementType.SqlExpression; } }
137
138 StringBuilder IQueryElement.ToString(StringBuilder sb, Dictionary<IQueryElement,IQueryElement> dic)
139 {
140 var len = sb.Length;
141 var ss = Parameters.Select(p =>
142 {
143 p.ToString(sb, dic);
144 var s = sb.ToString(len, sb.Length - len);
145 sb.Length = len;
146 return (object)s;
147 });
148
149 return sb.AppendFormat(Expr, ss.ToArray());
150 }
151
152 #endregion
153
154 #region Public Static Members
155
156 public static bool NeedsEqual(IQueryElement ex)
157 {
158 switch (ex.ElementType)
159 {
160 case QueryElementType.SqlParameter:
161 case QueryElementType.SqlField :
162 case QueryElementType.Column : return true;
163 case QueryElementType.SqlFunction :
164
165 var f = (SqlFunction)ex;
166
167 switch (f.Name)
168 {
169 case "EXISTS" : return false;
170 }
171
172 return true;
173 }
174
175 return false;
176 }
177
178 #endregion
179 }
180 }