PL/pgSQL multidimension (matrix) array in function
От | Sergio Fantinel |
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Тема | PL/pgSQL multidimension (matrix) array in function |
Дата | |
Msg-id | 4149C90D.60806@lnl.infn.it обсуждение исходный текст |
Ответы |
Re: PL/pgSQL multidimension (matrix) array in function
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Список | pgsql-sql |
I found how to use, inside a PL/pgSQL function, a two-dimensions array (matrix). There is a limitation: the number of the 'columns' of the matrix is fixed at declaration time (in DECLARE section) and you need to manually initialize all the elements in the first 'row' of the matrix. The number of rows is unlimited and can be sized at runtime. Here is the code that can help you. If someone know how to manage an NxN array without limitations, please replay to this thread. I'm using PostgreSQL 7.4.1 on RH7.3 CheersSergio CREATE OR REPLACE FUNCTION "testarray" (integer) RETURNS SETOF integer AS' DECLARE n alias for $1; -- number of rows is passed as argument i INTEGER; j integer; k INTEGER:= 3; -- matrix columns number b integer[] := array[0,0,0]; -- need it to initialize the matrix!! a integer[][] := array[[0,0,0]]; -- need it to initialize the matrix!! begin for i in 1..n loop -- the i loop can start obviously from 2 (the first row is already present...) but for our purpose here we use 1 a := array_cat(a,b); for j in 1..k loop a[i][j] := i*j; end loop; end loop; for i in 1..n loop return next null; return next i; -- need it to format in some way the output :) return nextnull; for j in 1..k loop return next a[i][j]; end loop; end loop; return; end 'LANGUAGE 'plpgsql'; here is the output: => select * from testarray(8); testarray ----------- 1 1 2 3 2 2 4 6 3 3 6 9 4 4 8 12 5 5 10 15 6 6 12 18 7 7 14 21 8 8 16 24 (48 rows) -- --------------------------------------------------------------------- Sergio Fantinel EGEE Project --------------------------------------------------------------------- INFN - Lab. Naz. di Legnaro phone: +39 049 8068 489 viale dell'Università n. 2, 35020 Legnaro (PD) ITALY sergio.fantinel@lnl.infn.it ---------------------------------------------------------------------
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