How can i read database from database row by row?

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Eman Shaltout
Eman Shaltout 2012-5-6
i need to select from database row by row this database built on appserve.
i need to read first row then second but i can't I try a lot . when i select all from database .all field are shown but i need to select row by row ,
also I can't get the true size of database by this function
size('my database name')
or
length('my database name')
I write in my code by using size of database
for i=1:c
for j=1:r
output=x(j,i)
%out=x(i,1)
end
end
cell2mat(x)
x(2,2)
%
  2 个评论
Geoff
Geoff 2012-5-6
Why do you want to read one row at a time? What is wrong with selecting all rows at once? You haven't shown the database query that you are using.
Eman Shaltout
Eman Shaltout 2012-5-7
I select all row and put result in variable but I need to search by row.....
QUERY = 'SELECT Feature , Feature2 , Feature3 FROM members '
[x]=fetch(dbConn,QUERY)

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采纳的回答

Juan B. Gutierrez
Juan B. Gutierrez 2012-5-17
Dear Eman, let me start by saying that you can access any relational database from MATLAB using many tools, including the Database toolbox, and the .NET and/or Java libraries.
The following example uses .NET data objects to connect to a MySQL database (you can connect with this method to ANY database; simply use the correct connection string), send a query, read row by row, and then load dataset columns into MATLAB variables. It is an expandeded version of the solution found at http://stackoverflow.com/questions/6593485/how-to-connect-to-microsoft-sql-server-2008-mssql-from-matlab. I hope this helps.
try
% Database conectivity parameters
host = '192.168.1.3'; % Insert your server's IP here
port = '3306'; % Default port for MySQL
user = 'yourUserName';
password = 'youUserPWD';
dbName = 'yourDatabase';
connString = ['Server=' host ';Port=' port ';Database=' dbName ...
';Uid=' user ';Pwd=' password ...
';Driver={MySQL ODBC 5.1 Driver};Option=3;'];
% Generate SQL query based upon input
sSQL = ['select * from table where' variableWithSQLConditions];
sSQL = char(sSQL);
% Connect to the database
var1 = []; var2 = []; var3=[];
NET.addAssembly('System.Data');
import System.Data.*
conn = Odbc.OdbcConnection(connString);
conn.Open();
dr = Odbc.OdbcCommand(sSQL, conn);
% Retrieve a record at a time
r = dr.ExecuteReader();
while r.Read()
var1 = [var1; str2double(char(r.GetString(0)))];
var2 = [var2 ; str2double(char(r.GetString(1)))];
var3 = [var3 ; str2double(char(r.GetString(2)))];
end
% Close connection
r.Close()
conn.Close()
catch err
cVars = err.message;
end

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