Class PhraseMaker

source code

                   object --+                    
                            |                    
 base.structure.StructureBase --+                
                                |                
                   object --+   |                
                            |   |                
           base.common.Parser --+                
                                |                
base.structure.ParseableStructure --+            
                                    |            
             base.structure.Structure --+        
                                        |        
                           object --+   |        
                                    |   |        
      base.structure.RestrictionMixin --+        
                                        |        
                   rscdef.procdef.ProcDef --+    
                                            |    
                       rscdef.procdef.ProcApp --+
                                                |
                                               PhraseMaker

A procedure application for generating SQL expressions from input keys.

PhraseMaker code must *yield* SQL fragments that can occur in WHERE clauses, i.e., boolean expressions (thus, they must be generator bodies). The clauses yielded by a single condDesc are combined with the joiner set in the containing CondDesc (default=OR).

The following names are available to them:

• inputKeys -- the list of input keys for the parent CondDesc
• inPars -- a dictionary mapping inputKey names to the values provided by the user
• outPars -- a dictionary that is later used as the parameter dictionary to the query.
• core -- the core to which this phrase maker's condDesc belongs

To get the standard SQL a single key would generate, say:

       yield base.getSQLForField(inputKeys[0], inPars, outPars)

To insert some value into outPars, do not simply use some key into outParse, since, e.g., the condDesc might be used multiple times. Instead, use getSQLKey, maybe like this:

       ik = inputKeys[0]
       yield "%s BETWEEN %%(%s)s AND %%(%s)s"%(ik.name,
               base.getSQLKey(ik.name, inPars[ik.name]-10, outPars),
               base.getSQLKey(ik.name, inPars[ik.name]+10, outPars))

getSQLKey will make sure unique names in outPars are chosen and enters the values there.