Selecting data from mysql using qt?
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ok here it is
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root@zafar-laptop:/# /opt/lampp/bin/mysql -u root -p 123456 testTwo
/opt/lampp/bin/mysql Ver 14.14 Distrib 5.1.41, for pc-linux-gnu (i686) using EditLine wrapper
Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL license
Usage: /opt/lampp/bin/mysql [OPTIONS] [database]
-?, --help Display this help and exit.
-I, --help Synonym for -?
--auto-rehash Enable automatic rehashing. One doesn't need to use
'rehash' to get table and field completion, but startup
and reconnecting may take a longer time. Disable with
--disable-auto-rehash.
-A, --no-auto-rehash
No automatic rehashing. One has to use 'rehash' to get
table and field completion. This gives a quicker start of
mysql and disables rehashing on reconnect. WARNING:
options deprecated; use --disable-auto-rehash instead.
-B, --batch Don't use history file. Disable interactive behavior.
(Enables --silent)
--character-sets-dir=name
Directory where character sets are.
--column-type-info Display column type information.
-c, --comments Preserve comments. Send comments to the server. The
default is --skip-comments (discard comments), enable
with --comments
-C, --compress Use compression in server/client protocol.
-#, --debug[=#] This is a non-debug version. Catch this and exit
--debug-check Check memory and open file usage at exit.
-T, --debug-info Print some debug info at exit.
-D, --database=name Database to use.
--default-character-set=name
Set the default character set.
--delimiter=name Delimiter to be used.
-e, --execute=name Execute command and quit. (Disables --force and history
file)
-E, --vertical Print the output of a query (rows) vertically.
-f, --force Continue even if we get an sql error.
-G, --named-commands
Enable named commands. Named commands mean this program's
internal commands; see mysql> help . When enabled, the
named commands can be used from any line of the query,
otherwise only from the first line, before an enter.
Disable with --disable-named-commands. This option is
disabled by default.
-g, --no-named-commands
Named commands are disabled. Use * form only, or use
named commands only in the beginning of a line ending
with a semicolon (;) Since version 10.9 the client now
starts with this option ENABLED by default! Disable with
'-G'. Long format commands still work from the first
line. WARNING: option deprecated; use
--disable-named-commands instead.
-i, --ignore-spaces Ignore space after function names.@
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@
--local-infile Enable/disable LOAD DATA LOCAL INFILE.
-b, --no-beep Turn off beep on error.
-h, --host=name Connect to host.
-H, --html Produce HTML output.
-X, --xml Produce XML output
--line-numbers Write line numbers for errors.
-L, --skip-line-numbers
Don't write line number for errors. WARNING: -L is
deprecated, use long version of this option instead.
-n, --unbuffered Flush buffer after each query.
--column-names Write column names in results.
-N, --skip-column-names
Don't write column names in results. WARNING: -N is
deprecated, use long version of this options instead.
-O, --set-variable=name
Change the value of a variable. Please note that this
option is deprecated; you can set variables directly with
--variable-name=value.
--sigint-ignore Ignore SIGINT (CTRL-C)
-o, --one-database Only update the default database. This is useful for
skipping updates to other database in the update log.
--pager[=name] Pager to use to display results. If you don't supply an
option the default pager is taken from your ENV variable
PAGER. Valid pagers are less, more, cat [> filename],
etc. See interactive help (\h) also. This option does not
work in batch mode. Disable with --disable-pager. This
option is disabled by default.
--no-pager Disable pager and print to stdout. See interactive help
(\h) also. WARNING: option deprecated; use
--disable-pager instead.
-p, --password[=name]
Password to use when connecting to server. If password is
not given it's asked from the tty.
-P, --port=# Port number to use for connection or 0 for default to, in
order of preference, my.cnf, $MYSQL_TCP_PORT,
/etc/services, built-in default (3306).
--prompt=name Set the mysql prompt to this value.
--protocol=name The protocol of connection (tcp,socket,pipe,memory).
-q, --quick Don't cache result, print it row by row. This may slow
down the server if the output is suspended. Doesn't use
history file.
-r, --raw Write fields without conversion. Used with --batch.
--reconnect Reconnect if the connection is lost. Disable with
--disable-reconnect. This option is enabled by default.
-s, --silent Be more silent. Print results with a tab as separator,
each row on new line.
-S, --socket=name Socket file to use for connection.
--ssl Enable SSL for connection (automatically enabled with
other flags). Disable with --skip-ssl.
--ssl-ca=name CA file in PEM format (check OpenSSL docs, implies
--ssl).
--ssl-capath=name CA directory (check OpenSSL docs, implies --ssl).
--ssl-cert=name X509 cert in PEM format (implies --ssl).
--ssl-cipher=name SSL cipher to use (implies --ssl).
--ssl-key=name X509 key in PEM format (implies --ssl).
--ssl-verify-server-cert
Verify server's "Common Name" in its cert against
hostname used when connecting. This option is disabled by
default.
-t, --table Output in table format.
--tee=name Append everything into outfile. See interactive help (\h)
also. Does not work in batch mode. Disable with
--disable-tee. This option is disabled by default.
--no-tee Disable outfile. See interactive help (\h) also. WARNING:
option deprecated; use --disable-tee instead
-u, --user=name User for login if not current user.
-U, --safe-updates Only allow UPDATE and DELETE that uses keys.
-U, --i-am-a-dummy Synonym for option --safe-updates, -U.
-v, --verbose Write more. (-v -v -v gives the table output format).
-V, --version Output version information and exit.
-w, --wait Wait and retry if connection is down.
--connect_timeout=# Number of seconds before connection timeout.
--max_allowed_packet=#
Max packet length to send to, or receive from server
--net_buffer_length=#
Buffer for TCP/IP and socket communication
--select_limit=# Automatic limit for SELECT when using --safe-updates
--max_join_size=# Automatic limit for rows in a join when using
--safe-updates
--secure-auth Refuse client connecting to server if it uses old
(pre-4.1.1) protocol
--server-arg=name Send embedded server this as a parameter.
--show-warnings Show warnings after every statement.Default options are read from the following files in the given order:
/etc/xampp/my.cnf /opt/lampp/etc/my.cnf ~/.my.cnf
The following groups are read: mysql client
The following options may be given as the first argument:
--print-defaults Print the program argument list and exit
--no-defaults Don't read default options from any options file
--defaults-file=# Only read default options from the given file #
--defaults-extra-file=# Read this file after the global files are read@
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Variables (--variable-name=value)
and boolean options {FALSE|TRUE} Value (after reading options)
auto-rehash FALSE
character-sets-dir (No default value)
column-type-info FALSE
comments FALSE
compress FALSE
debug-check FALSE
debug-info FALSE
database (No default value)
default-character-set latin1
delimiter ;
vertical FALSE
force FALSE
named-commands FALSE
ignore-spaces FALSE
local-infile FALSE
no-beep FALSE
host (No default value)
html FALSE
xml FALSE
line-numbers TRUE
unbuffered FALSE
column-names TRUE
sigint-ignore FALSE
port 3306
prompt mysql>
quick FALSE
raw FALSE
reconnect TRUE
socket /opt/lampp/var/mysql/mysql.sock
ssl FALSE
ssl-ca (No default value)
ssl-capath (No default value)
ssl-cert (No default value)
ssl-cipher (No default value)
ssl-key (No default value)
ssl-verify-server-cert FALSE
table FALSE
user root
safe-updates FALSE
i-am-a-dummy FALSE
connect_timeout 0
max_allowed_packet 16777216
net_buffer_length 16384
select_limit 1000
max_join_size 1000000
secure-auth FALSE
show-warnings FALSE@
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lyuts: yes \q is working too
doforumda: ok, so get into the mysql comand line with the command above
/opt/lampp/bin/mysql -D testTwo -h localhost -u root -p
and then do this:
grant all on testTwo.* to 'root'@'localhost' ;
Then we have a working mysql, and the rights are granted, we can get back to your Qt program.
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there is an error in sql syntax
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mysql> grant all on testTwo.* to ‘root’@’localhost’;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '��root’@’localhost’' at line 1
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Ok, back to your Qt program:
@#include <QApplication>
#include <QtSql>int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL"); db.setDatabaseName("testTwo"); db.setUserName("root"); db.setPassword(""); db.setHostName("localhost"); bool ok = db.open(); qDebug() << ok; QSqlQuery query; query.exec("SELECT firstname,lastname FROM testTable"); while(query.next()) { QString firstName = query.value(0).toString(); QString secondName = query.value(1).toString(); qDebug() << "First Name: " << firstName << "Last Name:" << secondName; qDebug() << db.lastError(); } return 0;}@
Notice, we don't set a password here.
The end is 'return 0' instead of 'a.exec()', and it won't hang. The exec() starts the main event loop, and you don't use it here...