Advice on Transfering functions from MS-MSSQL Server

Good Morning!

I've looked at the pgSQL docs but I'd like to get advice from someone thats
been "through the fire".

I'm attempting to move some code off of MS-SQL Server onto PostgreSQL. Most
of my MS code is written in Microsofts T-SQL Functions. I use a lot of
variables as well as Server-side cursors and temporary tables. Does this
need to be done in C or pg tcl or PL/pgSQL or am I better doing this sort of
thing on the client side. (thought I do need to protect the code as it is
proprietary)

Thanks in advance for any advice, below is a MS-SQL Function that is
simialar to the ones I need to transfer (with table & column names changed)

Darvin Zuch
mailto:darvin(dot)zuch(at)autoprofile(dot)com

CREATE PROCEDURE in_veBOXXERDecode @DINIV char(17), @DIROLOC int AS
DECLARE @TDText varchar(30), @ENIGNEText varchar(30), @DOBText varchar(30),
@TransText varchar(30), @SRSText varchar(30), @ModelText varchar(30),
@TSERText varchar(30), @GBRAText varchar(30), @GVWRText varchar(30),
@Braketext varchar(30), @LEUFText varchar(30), @HPText varchar(30),
@TypeText varchar(30), @MIRTText varchar(30), @DesignText varchar(30),
@EARText char(4), @KAMText varchar(30), @TDID int, @ENIGNEID int, @DOBID
int, @TransID int, @SRSID int, @ModelID int, @TSERID int, @GBRAID int,
@GVWRID int, @BrakeID int, @LEUFID int, @HPID int, @TypeID int, @MIRTID
int, @DesignID int, @EARID char(1), @KAMID int, @nTDID int,@nENIGNEID
int,@nDOBID int,@nTransID int,@nSRSID int, @nModelID int,@nTSERID
int,@nGBRAID int,@nGVWRID int,@nBrakeID int,@nLEUFID int, @nHPID
int,@nTypeID int,@nMIRTID int,@nDesignID int, @TGDCount tinyint, @TGDQty
tinyint, @OriginID int

SELECT @TGDCount = 0
SELECT @KAMID=IM.KAMID, @KAMText=KAM.KAMText, @EARID=IM.EARID,
@EARText=EAR.EARText, @OriginID = Origin.OriginID
FROM IM, KAM, EAR, Origin
WHERE IM.IMValue = SUBSTRING(@DINIV,1,3) AND
IM.EARID = SUBSTRING(@DINIV,10,1) AND
KAM.KAMID = IM.KAMID AND
EAR.EARID = IM.EARID AND
Origin.HCSID = IM.HCSID AND
Origin.OriginValue = SUBSTRING(@DINIV,11,1)

DECLARE in_vdDecodeBOXXER CURSOR FOR
SELECT VDS.TDID, VDS.ENIGNEID, VDS.DOBID, VDS.TransID, VDS.SRSID,
VDS.ModelID, VDS.TSERID, VDS.GBRAID, VDS.GVWRID, VDS.BrakeID, VDS.LEUFID,
VDS.HPID, VDS.TypeID, VDS.MIRTID, VDS.DesignID
FROM VDS, TGD, PYTXTGD, HCS, IM
WHERE VDS.HCSID = HCS.HCSID AND
VDS.TGDID = TGD.TGDID AND
VDS.VDSVALUE = SUBSTRING(@DINIV, TGD.START, TGD.LENGTH) and
TGD.TGDID = PYTXTGD.TGDID AND
PYTXTGD.PYTXID = HCS.PYTXID AND
HCS.HCSID = IM.HCSID AND
IM.IMVALUE = SUBSTRING(@DINIV, 1,3) AND
IM.EARID = SUBSTRING(@DINIV, 10,1)
OPEN in_vdDecodeBOXXER
FETCH in_vdDecodeBOXXER INTO @TDID, @ENIGNEID, @DOBID, @TransID, @SRSID,
@ModelID, @TSERID, @GBRAID, @GVWRID, @BrakeID, @LEUFID, @HPID, @TypeID,
@MIRTID, @DesignID
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT @TGDCount = @TGDCount + 1
SELECT @nTDID=Coalesce(@TDID,@nTDID),
@nENIGNEID=Coalesce(@ENIGNEID,@nENIGNEID),
@nDOBID=Coalesce(@DOBID,@nDOBID),
@nTransID=Coalesce(@TransID,@nTransID),
@nSRSID=Coalesce(@SRSID,@nSRSID),
@nModelID=Coalesce(@ModelID,@nModelID),
@nTSERID=Coalesce(@TSERID,@nTSERID),
@nGBRAID=Coalesce(@GBRAID,@nGBRAID),
@nGVWRID=Coalesce(@GVWRID,@nGVWRID),
@nBrakeID=Coalesce(@BrakeID,@nBrakeID),
@nLEUFID=Coalesce(@LEUFID,@nLEUFID),
@nHPID=Coalesce(@HPID,@nHPID),
@nTypeID=Coalesce(@TypeID,@nTypeID),
@nMIRTID=Coalesce(@MIRTID,@nMIRTID),
@nDesignID=Coalesce(@DesignID,@nDesignID)

FETCH in_vdDecodeBOXXER INTO @TDID, @ENIGNEID, @DOBID, @TransID, @SRSID,
@ModelID, @TSERID, @GBRAID, @GVWRID, @BrakeID, @LEUFID, @HPID, @TypeID,
@MIRTID, @DesignID
END
CLOSE in_vdDecodeBOXXER
DEALLOCATE in_vdDecodeBOXXER

IF EXISTS (SELECT DINIV FROM BOXXER WHERE DINIV = @DINIV)
UPDATE BOXXER
SET TDID = @nTDID, ENIGNEID = @nENIGNEID, DOBID = @nDOBID,
TransID = @nTransID, SRSID = @nSRSID, ModelID = @nModelID,
TSERID = @nTSERID, GBRAID = @nGBRAID, GVWRID = @nGVWRID,
BrakeID = @nBrakeID, LEUFID = @nLEUFID, HPID = @nHPID, TypeID = @nTypeID,
DesignID = @nDesignID, KAMID = @KAMID, EARID= @EARID, DIROLOC =
@DIROLOC,
OriginID = @OriginID
WHERE DINIV = @DINIV
ELSE
INSERT INTO BOXXER
( DINIV, EARID, KAMID, ModelID, SRSID, TDID, ENIGNEID, DOBID, TransID,
TSERID, GBRAID, GVWRID, BrakeID, LEUFID, HPID, TypeID, DesignID, DIROLOC,
OriginID)
VALUES
(@DINIV,
@EARID,@KAMID,@nModelID,@nSRSID,@nTDID,@nENIGNEID,@nDOBID,@nTransID,@nTSERID
,@nGBRAID,@nGVWRID,@nBrakeID,@nLEUFID,@nHPID,@nTypeID,@nDesignID, @DIROLOC,
@OriginID)