[Progress Communities] [Progress OpenEdge ABL] Forum Post: RE: Query parser

[Patrick Tingen]

I have a query library that does something similar, albeit not with classes. What I do to retrieve the tables used is this: FUNCTION openQuery RETURNS HANDLE ( INPUT pcQuery AS CHARACTER , INPUT pcBufferList AS CHARACTER ): /* Name: openQuery * Desc: Create and open a dynamic query with all its buffers. * * You can define alternative names for a buffer: * * hQuery = openQuery( 'FOR EACH thingy, EACH order OF thingy' * , 'thingy=customer, order' * ). * * If the 2nd parameter is optional if you use standard buffer names. * You can also provide buffer handles as follows: * * hQuery = openQuery( 'FOR EACH ttCustomer' * , SUBSTITUTE('ttCustomer=&1', BUFFER ttCustomer:handle' * ). * * If you want to use temp-tables, you need to provide buffer handles */ DEFINE VARIABLE cBuffer AS CHARACTER NO-UNDO. DEFINE VARIABLE cEntry AS CHARACTER NO-UNDO. DEFINE VARIABLE cErrorList AS CHARACTER NO-UNDO. DEFINE VARIABLE cNextWord AS CHARACTER NO-UNDO. DEFINE VARIABLE cQuery AS CHARACTER NO-UNDO. DEFINE VARIABLE cTable AS CHARACTER NO-UNDO. DEFINE VARIABLE cWord AS CHARACTER NO-UNDO. DEFINE VARIABLE hBuffer AS HANDLE NO-UNDO. DEFINE VARIABLE hQuery AS HANDLE NO-UNDO. DEFINE VARIABLE iBuffer AS INTEGER NO-UNDO. DEFINE VARIABLE iError AS INTEGER NO-UNDO. DEFINE VARIABLE iWord AS INTEGER NO-UNDO. DEFINE VARIABLE lPrepared AS LOGICAL NO-UNDO. /* Create a list of buffers */ IF pcBufferList = '' THEN DO: cQuery = pcQuery. cQuery = REPLACE(cQuery,',',' '). /* To separate all words */ /* Remove double spaces */ REPEAT WHILE INDEX(cQuery," ") > 0: cQuery = REPLACE(cQuery,' ', ' '). END. /* Walk thru the query to collect table names */ DO iWord = 1 TO NUM-ENTRIES(cQuery,' ') - 1: cWord = ENTRY(iWord,cQuery,' '). cNextWord = ENTRY(iWord + 1,cQuery,' '). IF LOOKUP(cWord,'EACH,FIRST,LAST') > 0 AND LOOKUP(cNextWord,pcBufferList) = 0 THEN pcBufferList = TRIM(pcBufferList + ',' + cNextWord,','). END. PUBLISH 'debugMessage' (1, SUBSTITUTE('Automatically collected buffers: &1', pcBufferList)). END. CREATE QUERY hQuery. DO iBuffer = 1 TO NUM-ENTRIES(pcBufferList): cEntry = TRIM(ENTRY(iBuffer, pcBufferList)). cBuffer = ENTRY( 1, cEntry ,'='). cTable = ENTRY(NUM-ENTRIES(cEntry,'='), cEntry,'='). /* Remove database reference from buffer name */ cBuffer = ENTRY(NUM-ENTRIES(cBuffer,'.'), cBuffer,'.'). /* Try to interpret the buffer name as a handle */ hBuffer = ?. hBuffer = WIDGET-HANDLE(cTable) NO-ERROR. /* If that works, then we received a buffer handle */ IF VALID-HANDLE(hBuffer) THEN DO: /* Then don't do anything, but use the buffer provided */ PUBLISH 'debugMessage' (1, SUBSTITUTE('Use buffer "&1" for table "&2"', cTable, cBuffer )). END. ELSE DO: /* Just a name, so create a buffer for this table */ CREATE BUFFER hBuffer FOR TABLE cTable BUFFER-NAME cBuffer NO-ERROR. PUBLISH 'debugMessage' (1, SUBSTITUTE('Create buffer for table "&1"', cTable)). END. IF ERROR-STATUS:ERROR THEN RETURN ?. hQuery:ADD-BUFFER(hBuffer). END. lPrepared = hQuery:QUERY-PREPARE(pcQuery) NO-ERROR. IF lPrepared THEN hQuery:QUERY-OPEN. ELSE DO: /* Collect errors */ DO iError = 1 TO ERROR-STATUS:NUM-MESSAGES: cErrorList = cErrorList + CHR(1) + ERROR-STATUS:GET-MESSAGE(iError). END. cErrorList = TRIM(cErrorList,CHR(1)). PUBLISH 'debugMessage' (2, 'Errors opening query:' ). DO iError = 1 TO NUM-ENTRIES(cErrorList,CHR(1)): PUBLISH 'debugMessage' (2, ENTRY(iError,cErrorList,CHR(1)) ). END. hQuery = ?. END. RETURN hQuery. END FUNCTION. /* openQuery */ DEFINE VARIABLE hQuery AS HANDLE NO-UNDO. hQuery = openQuery('for each customer no-lock',''). REPEAT WHILE hQuery:GET-NEXT(): DISPLAY hQuery:GET-BUFFER-HANDLE(1)::cust-num hQuery:GET-BUFFER-HANDLE(1)::NAME FORMAT 'x(30)'. END.

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