hunt.database.query.Expression source code

1 module hunt.database.query.Expression;
2 
3 import hunt.database.query.Common;
4 
5 class Expression
6 {
7     string value;
8 }
9 
10 class WhereExpression : Expression
11 {
12     string key;
13     string op;
14     string value;
15     this(string key , string op, string value)
16     {
17         this.key = key;
18         this.op = op;
19         this.value = value;
20     }
21     string formatKey(string str)
22     {
23         return str;
24     }
25     string formatValue(string str)
26     {
27         if(str == null)return "null";
28         return str;
29     }
30     override string toString()
31     {
32         return formatKey(key) ~ " " ~ op ~ " "~ formatValue(value);
33     }
34 }
35 
36 class ValueExpression : Expression
37 {
38     string key;
39     string value;
40     this(string key , string value)
41     {
42         this.key = key;
43         this.value = value;
44     }
45     override string toString()
46     {
47         return  key ~ " = " ~ value ;
48     }
49 }
50 
51 class JoinExpression : Expression
52 {
53     JoinMethod _join;
54     string _table;
55     string _tableAlias;
56     string _on;
57     this(JoinMethod join,string table,string tableAlias,string on)
58     {
59         _join = join;
60         _table = table;
61         _tableAlias = tableAlias;
62         _on = on;
63     }
64     override string toString()
65     {
66         string str = " " ~ _join ~ " " ~ _table ~ " " ~ _tableAlias ~ " ";
67         if(_join != JoinMethod.CrossJoin) str ~= " ON " ~ _on ~ " ";
68         return str;
69     }
70 }
71 
72 class MultiWhereExpression : Expression
73 {
74     Relation _relation;
75     MultiWhereExpression[] childs;
76     WhereExpression expr;
77     override string toString()
78     {
79         if(childs.length){
80             auto len = childs.length;
81             int i = 0;
82             string str;
83             foreach(child;childs)
84             {
85                 str ~= child.toString;
86                 if( i < len-1 )str ~=  (_relation == Relation.And ? " AND " : " OR ");
87                 i++;
88             }
89             return "(" ~ str ~ ")";
90         }else{
91             return "(" ~ expr.toString ~ ")";
92         }
93     }
94     MultiWhereExpression eq(string key,string value)
95     {
96         if(value == null)
97         expr = new WhereExpression(key,"is",null);
98         else 
99         expr = new WhereExpression(key,"=",value);
100         return this;
101     }
102     MultiWhereExpression ne(string key,string value)
103     {
104         if(value == null)
105         expr = new WhereExpression(key,"is not",null);
106         else 
107         expr =  new WhereExpression(key,"!=",value);
108         return this;
109     }
110     MultiWhereExpression gt(string key,string value)
111     {
112         expr =  new WhereExpression(key,">",value);
113         return this;
114     }
115     MultiWhereExpression lt(string key,string value)
116     {
117         expr = new WhereExpression(key,"<",value);
118         return this;
119     }
120     MultiWhereExpression ge(string key,string value)
121     {
122         expr = new WhereExpression(key,">=",value);
123         return this;
124     }
125 MultiWhereExpression le(string key,string value)
126 {
127     expr = new WhereExpression(key,"<=",value);
128     return this;
129 }
130 MultiWhereExpression like(string key,string value)
131 {
132     expr = new WhereExpression(key,"like",value);
133     return this;
134 }
135 MultiWhereExpression andX(T...)(T args)
136 {
137     _relation = Relation.And; 
138     foreach(v;args)
139     {
140         childs ~= v;
141     }
142     return this;
143 }
144 MultiWhereExpression orX(T...)(T args)
145 {
146     _relation = Relation.Or; 
147     foreach(v;args)
148     {
149         childs ~= v;
150     }
151     return this;
152 }
153 }