Re: octave and postgres examples

[richard]

On Wed, Jun 19, 2013 at 04:36:10PM -0400, Thomas Grzybowski wrote:
> Hi,
> 
> I have been trying to connect octave to my postgres database using
> the 'database' Package - obtained from Octave-Forge - SourceForge,
> and written and maintained by Olaf Till.
> 
> I am able to create a connection object ("conn"), as so:
> 
> conn = pq_connect(setdbopts("host", "localhost","dbname", "tg",
> "user", "tg", "password", ""));
> 
> I know some SQL, but I am unfamiliar with the octave side of things;
> I am trying to use the command "pq_exec_params", but the
> documentation is a little sparse on the syntax.
> 
> I could really use some examples of reading and writing tables to
> and from octave arrays.  If anyone could post some example code that
> would be very much appreciated.
> 
A work in progress hence it is kinda rough ... 
##############constants and initial conditions ############################
# Set up the E matrix, initialise with ones
E= ones(50); 
E(1) = 0.03 ; # (rl) Interest on loan =0.05
E(2) = 0.01 ; # (rd) Interest on Deposit =0.01
E(3) = 0.1 ;  # (Ow) Omega
E(4) = 0.16;  # sigma (0.27) *sigma up, inflation up*
E(5) = 3 ;    # (v) Output accelerator
E(6) = 300 ;  # (N) Population available to the Economy
E(7) = 0.03;  # (g) GDP growth rate - *redundant value* 
E(8) = 300;   # (L) Population employed in the economy *redundant value* 
E(9) = 900;   # (K) Wealth available to the economy *redundant value*
E(10)= 1 ;    # (II) Employment ratio "redundant value" = 1
E(11)= 300;   # (K/v) Current real Capital *redundant value*
E(12)= 0.01; # (Alpha) rate of change of productivity from Capital and Labour: 
alpha up, capital up, inflation slightly dn 
E(13)= 0.0048;  # (Beta) rate of change of Population available to the Economy 
E(14)= 0.009;  #0.01;  # (Delta) A bias toward negative growth
E(15)= 0.038461538; # (Torw=1/26) rate of expenditure of Wages
E(16)= 1.0;   # (Torp) time lag for price changes
E(17)= 1.0;   # (Torb) time lag for bank
E(18)= 0.0593; # (PIr) profit rate *redundant value* 
E(19)= 1.0;   # (Minsky) Speculation occurring within the system *redundant 
value* 
E(20)= 1.0;   # (Winf) wage inflation 
E(21)= 135.0;  # (Tauc) decay time for capital invested productively 
E(22) =0.95;E(23)=0;E(24)=2;E(25)=-0.04; # constants for wage inflation 
Phillips function Ph(II,x,y,s,m)
E(26)=0.04;E(27)=0.04;E(28)=2;E(29)=0;   # constants for Investment Phillips 
function Inv(PIr,x1,y1,s1,m1)
E(30)=0.03;E(31)=10;E(32)=100;E(33)=3;   # constants for Firms timelag Phillips 
function Taurl(PIr,x2,y2,s2,m2)
E(34)=0.03;E(35)=2;E(36)=-50;E(37)=0.5;  # constants for Bank timelag Phillips 
function Taulc(PIr,x3,y3,s3,m3)
E(38)=0.15;E(39)=0.33;E(40)=5;E(41)=0;   # constants for wage timelag Phillips 
function Winf( ,x4,y4,s4,m4)
E(42)=15.65;                             # government spending rate on Army 
E(43)=0.04;                              # government tax revenue pu of GDP (Y)
E(44)=0.010;                             # interest on government debt
E(45)=5.60;                              # government stimulus - Emperor 
spending pa
E(46)= 6.0;                              # Emperors non-tax income eg Egypt
E(47)= 1;                                # Inflation divisor for government 
spending
E(48)= 0;                              # Government discretionary spending inc 
welfare
########################################################################
E00="Augustus";
E01=E(01); E02=E(02); E03=E(03); E04=E(04); E05=E(05);
E06=E(06); E07=E(07); E08=E(08); E09=E(09); E10=E(10);
E11=E(11); E12=E(12); E13=E(13); E14=E(14); E15=E(15);
E16=E(16); E17=E(17); E18=E(18); E19=E(19); E20=E(20);
E21=E(21); E22=E(22); E23=E(23); E24=E(24); E25=E(25);
E26=E(26); E27=E(27); E28=E(28); E29=E(29); E30=E(30);
E31=E(31); E32=E(32); E33=E(33); E34=E(34); E35=E(35);
E36=E(36); E37=E(37); E38=E(38); E39=E(39); E40=E(40);
E41=E(41); E42=E(42); E43=E(43); E44=E(44); E45=E(45);
E46=E(46); E47=E(47); E48=E(48); E49=E(49); E50=E(50);

#####################################################
 pkg load database   # the autoload for database is unset usually
  conn = pq_connect (setdbopts ("host", "localhost", "dbname", "rome", "user", 
"user", "password", "secret"));
pq_exec_params (conn, "select * from Ematrix01;"); #
 S = pq_exec_params (conn, "select * from Ematrix01")
########################################################
# num2str(cell2mat(S.data(1,1)));      # strings, numbers and matricies 
  try,  pq_exec_params (conn, "drop table ematrix01;"); catch end_try_catch
pq_exec_params (conn, "create table ematrix01 (E00 varchar PRIMARY KEY,\
E01 float4,E02 float4, E03 float4, E04 float4, E05 float4,\
E06 float4,E07 float4, E08 float4, E09 float4, E10 float4,\
E11 float4,E12 float4, E13 float4, E14 float4, E15 float4,\
E16 float4,E17 float4, E18 float4, E19 float4, E20 float4,\
E21 float4,E22 float4, E23 float4, E24 float4, E25 float4,\
E26 float4,E27 float4, E28 float4, E29 float4, E30 float4,\
E31 float4,E32 float4, E33 float4, E34 float4, E35 float4,\
E36 float4,E37 float4, E38 float4, E39 float4, E40 float4,\
E41 float4,E42 float4, E43 float4, E44 float4, E45 float4,\
E46 float4,E47 float4, E48 float4, E49 float4, E50 float4\
);");

X = "insert into Ematrix01 (E00";                #) values";
#X = "insert into Ematrix01 (E01, E02, E03, E04, E05) values";
XX = ", E01, E02, E03, E04, E05, E06, E07, E08, E09, E10";
X = cstrcat(X, XX);
XX = ", E11, E12, E13, E14, E15, E16, E17, E18, E19, E20";
X = cstrcat(X, XX);
XX = ", E21, E22, E23, E24, E25, E26, E27, E28, E29, E30";
X = cstrcat(X, XX);
XX = ", E31, E32, E33, E34, E35, E36, E37, E38, E39, E40";
X = cstrcat(X, XX);
XX = ", E41, E42, E43, E44, E45, E46, E47, E48, E49, E50";
X = cstrcat(X, XX);
XX=") values";
X = cstrcat(X, XX);

Y = ["(","'" E00"'",];                          #);"];
j=0; while (j< 42) 
 a1= num2str(E(j+1));
 a2= num2str(E(j+2));
 a3= num2str(E(j+3));
 a4= num2str(E(j+4));
 a5= num2str(E(j+5));
 a6= num2str(E(j+6));
 a7= num2str(E(j+7));
 a8= num2str(E(j+8));
 a9= num2str(E(j+9));
 a10= num2str(E(j+10));
YY = ["," a1,", ", a2,", " a3, ", ", a4, ", ", a5, ", ", a6,", ", a7,", " a8, 
", ", a9, ", ", a10, ];
Y = cstrcat(Y, YY);
j=j+10;
endwhile
YY= [");"];
Y = cstrcat(Y, YY);
Z = cstrcat(X, Y);
pq_exec_params (conn, Z);

HTH

Richard A Lough