Linux应用集成MySQL数据库访问技巧

#This code prints out all products in the database
# that are below a specified price (assumed to have been determined
# beforehand, and stored in the variable targetPrice)
# The output is in HTML table format, appropriate for CGI output

#load the SQL shared object library. the Tcl interpreter could also
#have been compiled with the library, making this line unnecessary
load /home/aroetter/tcl-sql/sql.so

#these are well defined beforehand, or they could
#be passed into the script
set DBNAME "clientWebSite";
set TBLNAME "products";
set DBHOST "backend.company.com"
set DBUSER "mysqluser"
set DBPASSWD "abigsecret"

set targetPrice 200;

#connect to the database
set handle [sql connect $DBHOST $DBUSER $DBPASSWD]
sql selectdb $handle $DBNAME ;# get test database

#run a query using the specified sql code
sql query $handle "select * from $TBLNAME where price <= $targetPrice"


#print out html table header
puts ""
puts "
Product Id 
Description 
Price (\$)"

#output table rows - each fetchrow retrieves one result
#from the sql query
while {[set row [sql fetchrow $handle]] != ""} {
    set prodid [lindex $row 0]
    set descrip [lindex $row 1]
    set price [lindex $row 2]
    puts "
$prodid 
$descrip 
$price"
}

puts "
"

#empty the query result buffer - should already be empty in this case
sql endquery $handle
#close the db connection - in practice this same connection
#is used for multiple queries
sql disconnect $handle

#include 
#include 
#include 

const char *DBNAME = "clientWebSite";
const char *DBTABLE = "products";
const char *DBHOST = "backend.company.com";
const char *DBUSER = "mysqluser";
const char *DBPASSWD = "abigsecret":

int main() {
  try {
    //open the database connection and query
    Connection con(DBNAME, DBHOST, DBUSER, DBPASSWD);
    Query query = con.query();

    //write valid sql code to the query object
    query << "select * from " << DBTABLE;

    //run the query and store the results
    Result res = query.store();

    //write out the html table header
    cout << "\n";
    cout << "
Product Id 
Description"
 << "
Price ($)" << endl;

    Result::iterator curResult;
 Row row;

    //iterate over each result and put it into an html table
    for (curResult = res.begin(); curResult != res.end(); curResult++) {
      row = *curResult;
      cout << "
" << row[0]
         << "
" << row[1]
         << "
" << row[2] << endl;

    }
    cout << "
" << endl;

  } catch (BadQuery er) {
    // handle a bad query (usually caused by a sql syntax error)
    cerr << "Error: " << er.error <<  endl;
    return -1;

  } catch (BadConversion er) {
//handle conversion errors out of the database as well
    cerr << "Error: Can't convert \"" << er.data << "\" to a \""
 << er.type_name << "\"." << endl;
    return -1;
  }
  return 0;
}