Release 10.1A: OpenEdge Development:
Progress 4GL Handbook

Creating a dynamic temp-table

Next, look at a few parts of procedure h-gettemptable.p.

The main block creates a dynamic query for the database tables requested (such as Order and Customer). The createBuffers procedure creates a dynamic buffer for each of those tables.

The getFieldHandles procedure assembles a list of the handles to the fields requested (such as Order.OrderNum).

The createTempTable procedure creates a dynamic temp-table called hTT, and adds iCount to it as its first field:

/* Create the temp table */   CREATE TEMP-TABLE hTT.  /* Add a count field - we need this for the sequence so that we get the records     back in the order that they were created */   hTT:ADD-NEW-FIELD("iCount","INTEGER").

It then walks through the list of database field handles and adds a field to the temp-table like each field:

/* Iterate through the list of field handles in the cTableFields */   DO iCount = 1 TO NUM-ENTRIES(cTableFields):     /* Convert the current entry to a handle */     hField = WIDGET-HANDLE(ENTRY(iCount,cTableFields)).     /* Add a field to the temp table like this field with the same name as this       field */     hTT:ADD-LIKE-FIELD(hField:NAME,hField).   END.

It then adds an index on iCount, so that the records remain in the order they were created:

/* Add a primary unique index to the temp-table */   hTT:ADD-NEW-INDEX("pudx",True,True).   /* Add the counter field to the index */   hTT:ADD-INDEX-FIELD("pudx","iCount").

Finally, it prepares the temp-table, which freezes its definition and enables you to add records to it:

/* Prepare the temp-table with the name the user chose */    hTT:TEMP-TABLE-PREPARE(icTableName).

Next, the h-gettemptable.p procedure populates the temp-table in the populateTempTable internal procedure. Handle hTTBuf holds the handle to the temp-table’s default buffer:

/* Store the handle to the buffer for the temp-table */    hTTBuff = hTT:DEFAULT-BUFFER-HANDLE.

The procedure prepares the database query with the FOR EACH statement entered in the dialog box, opens it, and retrieves the first record:

/* Prepare a query using the string the user provided */   hQuery:QUERY-PREPARE(icForEach).   /* Open the query */   hQuery:QUERY-OPEN().   /* Get the first result in the result set */   hQuery:GET-FIRST().

For as many rows as there are in the query, or as many rows as you asked for, whichever is less, the procedure creates a temp-table row using the buffer handle:

/* Iterate for as many rows as the user has chosen, or until the query is      off-end */   REPEAT iCount = 1 TO iiRows WHILE NOT hQuery:QUERY-OFF-END:     /* Create a temp-table record */     hTTBuff:BUFFER-CREATE().

Because you selected individual fields from possibly multiple tables in the database to add to the temp-table, it doesn’t do a BUFFER-COPY to move fields from the database records to the newly created temp-table row. Instead, the next block of code uses the BUFFER-FIELD and BUFFER-VALUE attributes on both the database buffer fields and the temp-table buffer fields to move values from one to the other.

The procedure then releases each temp-table row, iterates through the query until the REPEAT condition fails, and then closes the query:

/* Release the temp-table record */     hTTBuff:BUFFER-RELEASE().     /* Get teh next result in the query */     hQuery:GET-NEXT().   END.   /* Close the query */   hQuery:QUERY-CLOSE().