For a few days I'm trying to find a way to read from a database via a sketch.
I found some examples WRITING to a database like
Tried it. Works fine.
But now, how to READ....?
I tried the following code that did not crash, but did not produce results as well.
void runSqlQuery_GetName()
{
int iNumber = 0;
String sName = "";
// Start a shell process to run a command in the OS.
Process p;
// Which SQL engine are we going to use
String cmd = "sqlite3 ";
// commandline input
String paramstring1 = "-line " ;
// set the path and name of your database here
String paramstring2 ="/DB/test1.db ";
// insert a row with a number and a name
String paramstring3 ="'SELECT * FROM Name ;'";
// get the error code
String paramstring4 =" ; echo $?";
p.runShellCommand(cmd + paramstring1 + paramstring2 + paramstring3+ paramstring4);
Serial.println("process run: '" + cmd + paramstring1 + paramstring2 + paramstring3+ paramstring4 + "'");
// A process output can be read with the stream methods
while (p.available()>0) {
char c = p.read();
if (c > 0)
{
Serial.print(c);
break;
}
}
// Ensure the last bit of data is sent.
Serial.flush();
Serial.println("Done");
}
sqlite> create table tbl1(one varchar(10), two smallint);
sqlite> insert into tbl1 values('hello!',10);
sqlite> insert into tbl1 values('goodbye', 20);
use Control+Z to exit sqlite shell
root@Arduino:/usr/bin/sqlite3 -csv -header /mnt/sda1/test.db "select * from tbl1;"
#include <Process.h>
void setup() {
Bridge.begin(); // Initialize the Bridge
Serial.begin(9600); // Initialize the Serial
// Wait until a Serial Monitor is connected.
while (!Serial);
}
void loop() {
Process p;
p.runShellCommand("/usr/bin/sqlite3 -csv -header /mnt/sda1/test.db \"select * from tbl1;\"");
// do nothing until the process finishes, so you get the whole output:
while (p.running());
// Read command output. runShellCommand()
while (p.available()>0) {
char c = p.read();
Serial.print(c);
}
Serial.flush();
Serial.println("Done");
while(1) { };
}
void runSqlQuery_GetName()
{
int iNumber = 0;
String sName = "";
// Start a shell process to run a command in the OS.
Process p;
String sCommand = "/usr/bin/sqlite3 -csv /DB/test1.db 'SELECT * FROM Name;' ";
p.runShellCommand(sCommand);
Serial.println (sCommand);
// do nothing until the process finishes, so you get the whole output:
while (p.running());
// Read command output. runShellCommand()
while (p.available()>0) {
char c = p.read();
Serial.print(c);
}
Serial.flush();
Serial.println("Done");
}
Result:
1,Rens
I knew I was making things to difficult.
Thank you very much.
Fbo06:
Hello RensD, can you please explain to me where you got the files who are on the www of the yunadventure subfolder ?
thank you very much for helping
Hi. Of cause I would like to help you, but I hac no idea what you are referring to.
please explain, so I can sit you.
