1 martin 1.9 //%LICENSE////////////////////////////////////////////////////////////////
  2            // 
  3            // Licensed to The Open Group (TOG) under one or more contributor license
  4            // agreements.  Refer to the OpenPegasusNOTICE.txt file distributed with
  5            // this work for additional information regarding copyright ownership.
  6            // Each contributor licenses this file to you under the OpenPegasus Open
  7            // Source License; you may not use this file except in compliance with the
  8            // License.
  9            // 
 10            // Permission is hereby granted, free of charge, to any person obtaining a
 11            // copy of this software and associated documentation files (the "Software"),
 12            // to deal in the Software without restriction, including without limitation
 13            // the rights to use, copy, modify, merge, publish, distribute, sublicense,
 14            // and/or sell copies of the Software, and to permit persons to whom the
 15            // Software is furnished to do so, subject to the following conditions:
 16            // 
 17            // The above copyright notice and this permission notice shall be included
 18            // in all copies or substantial portions of the Software.
 19            // 
 20            // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 21            // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
 22 martin 1.9 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 23            // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 24            // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 25            // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 26            // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 27 mike   1.2 // 

 28 martin 1.9 //////////////////////////////////////////////////////////////////////////

 29 mike   1.2 //
 30            //%/////////////////////////////////////////////////////////////////////////////
 31            
 32            #ifndef Pegasus_WQLOperation_h
 33            #define Pegasus_WQLOperation_h
 34            
 35            #include <Pegasus/Common/Config.h>
 36            #include <Pegasus/WQL/Linkage.h>
 37            
 38            PEGASUS_NAMESPACE_BEGIN
 39            
 40            /** Represents SQL where clause operators.
 41            
 42                These operators include the following:
 43            
 44                <ul>

 45 karl   1.8         <li>OR</li>
 46                    <li>AND</li>
 47                    <li>NOT</li>
 48                    <li>=</li>
 49                    <li>&lt;&gt;</li>
 50                    <li>&lt;</li>
 51                    <li>&le;</li>
 52                    <li>&gt;</li>
 53                    <li>&ge;</li>
 54                    <li>IS NULL</li>
 55                    <li>IS NOT NULL</li>
 56                    <li>IS TRUE</li>
 57                    <li>IS NOT TRUE</li>
 58                    <li>IS FALSE</li>
 59                    <li>IS NOT FALSE</li>

 60 mike   1.2     </ul>
 61            
 62                Here's an example of a SQL query that uses some of these operations.
 63            
 64                <pre>

 65 karl   1.8         SELECT *
 66                    FROM MyClass
 67                    WHERE (x > 10 OR y ≤ 1.5) OR z = 19 AND name IS NOT NULL

 68 mike   1.2     </pre>
 69            
 70                As the parser recognizes these operations, it adds the corresponding
 71                WQLOperation enumeration tag to the WQLSelectStatement by calling
 72                WQLSelectStatement::appendOperation().
 73            
 74                Operators may be converted to string by calling WQLOperationToString().
 75            
 76                Note that in expressions like this one:
 77            
 78                <pre>

 79 karl   1.8         count IS TRUE

 80 mike   1.2     </pre>
 81            
 82                The IS operator is NOT treated as a binary operator (which would take
 83                count and TRUE as its operands). Instead, the IS operator and TRUE operand
 84                are combined to form a single unary operation called "IS_TRUE". In this 
 85                way, evaluation may be implemented by more efficiently (the TRUE operand
 86                is eliminated and therefore need not be handled). Conceptually, the above
 87                expression is equivalent to the following psuedo expression:
 88            
 89                <pre>

 90 karl   1.8         IS_TRUE(count)

 91 mike   1.2     </pre>
 92            
 93                Note that this technique is applied the following operations (also 
 94                combined to be unary operations).
 95            
 96                <ul>

 97 karl   1.8         <li>WQL_IS_NULL</li>
 98                    <li>WQL_IS_NOT_NULL</li>
 99                    <li>WQL_IS_TRUE</li>
100                    <li>WQL_IS_NOT_TRUE</li>
101                    <li>WQL_IS_FALSE</li>
102                    <li>WQL_IS_NOT_FALSE</li>

103 mike   1.2     </ul>
104            */
105            enum WQLOperation
106            {
107                WQL_OR,
108                WQL_AND,
109                WQL_NOT,
110                WQL_EQ,
111                WQL_NE,
112                WQL_LT,
113                WQL_LE,
114                WQL_GT,
115                WQL_GE,
116                WQL_IS_NULL,
117                WQL_IS_NOT_NULL,
118                WQL_IS_TRUE,
119                WQL_IS_NOT_TRUE,
120                WQL_IS_FALSE,
121                WQL_IS_NOT_FALSE
122            };
123            
124 mike   1.2 PEGASUS_WQL_LINKAGE const char* WQLOperationToString(WQLOperation x);
125            
126            PEGASUS_NAMESPACE_END
127            
128            #endif /* Pegasus_WQLOperation_h */