While I am just learning MySQL and MySQLWorkbench, and have perhaps have done something boneheaded, I cannot find a reference to this.
Suddenly, no matter what line of code or what query I run, it outputs the same response even if I query for tables disconnected to the response. The database tests connected. I have run the use command. I have tried to google hack this and found nothing close to my situation. It was running just fine. I did not change the database. I was just running some very basic SELECT queries.
Any ideas?
Did you check your installation ?
Related
I'm learning SQL / MySQL using WAMPSERVER and the MySql extension for vsCode, so that I can write, comment and keep the code in the vsCode editor, instead of sending volatile queries with the command line.
This morning I created a database by right-clicking a database / New Query:
After creating it this way, I was able to create code that I run without having to write USE DBaseName before the selected lines, as in the selected three lines you can see below:
Yet, after restarting my laptop at home, the same code will not run. It returns the usual
undefined
Error: ER_NO_DB_ERROR: No database selected
unless I write the USE statement, as in the last group (4 lines) of code. So I have to write that every time I want to try a query...
Why did it work this morning and not now? How can one run queries without having to constantly write USE DBaseName?
(links to explanations to further understand the underlying mechanism are also very welcome...)
EDIT: posting image of server in vsCode to answer comment:
I'm using a local server (pic below) which hasn't changed since this morning...
I've just readl the Database Code Completion while working in PHP on your web support. So I've configured the database, I can complete the queries with ctrl+enter but I can't run query on console. I send you some pictures to explain the problem.
I've the database configured, so I can check the tables and all the dates, and run queries directly at the console, but can't send from php the query.
Thanks for all, Manu.
You need to connect to the DB before you run any queries on it (example in MySQL here: http://www.w3schools.com/php/php_mysql_connect.asp, don't forget to close it when you don't need it anymore. )
The result is not plain text, you need to go through it in a loop (example including the connection here: http://www.w3schools.com/php/php_mysql_select.asp ).
I'm using sails.js and I have a MySQL DB.
My connection and everything working perfectly.
As far as I understand, Sails connect to all DB's on lift.
But what if the connection is lost for 1-2 sec.?
How can I auto-reconnect to the DB, or set attempts to exec the query?
Is there any option to override the function that executing the query, so I can put a try catch and make it recursive or something like that?(of course this change need to be applied to all my servers, so overriding the module itself in the node-module folder is a little bit problem..
Thanks in advance!
sails automatically does this. If you console.log() query result you will see it will print multiple time and it will continue.
I have been unable to determine what the cause of the following Sequel::PoolTimeout error is coming from in a Ruby script I have written:
Sequel::PoolTimeout: Sequel::PoolTimeout
hold at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/connection_pool/threaded.rb:100
hold at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/connection_pool/threaded.rb:93
synchronize at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/database/connecting.rb:234
execute at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/adapters/jdbc.rb:258
execute at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:793
fetch_rows at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/adapters/jdbc.rb:671
each at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:143
single_record at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:583
single_value at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:591
get at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:250
empty? at /Users/username/.rvm/gems/jruby-1.7.4#all/gems/sequel-4.2.0/lib/sequel/dataset/actions.rb:153
scrap at /Users/username/projectname/processers/get_category.rb:46
each at org/jruby/RubyArray.java:1617
each_with_index at org/jruby/RubyEnumerable.java:920
scrap at /Users/username/projectname/processers/get_category.rb:44
scrap at /Users/username/projectname/processers/get_category.rb:32
I have tried this with both MRI and JRuby with exactly the same results.
As per the instructions on the Sequel gem here, I have attempted to raise the pool_timeout limit as follows:
DB = Sequel.connect("jdbc:mysql://localhost/project_db?user=USERNAME&password=PASSWD&max_connections=10&pool_timeout=120")
It seems as though the max_connections and pool_timeout may not be recognized, however I'm not seeing any other way to pass these args on into the connection.
The actual code that is in question here is:
if DB[:products].where(url: url.to_s).empty?
I have seen the code work just fine for a little bit, but without fail it fails either right away or after a couple minutes without any reproducibility in terms of when it occurs. I am starting to suspect that this is a MySQL config issue or something causing the localhost DBMS to have some prolonged delays, although, again, I cannot manually reproduce a visible timeout that I can tell with manual queries, etc.
Any ideas on this issue as to why the timout would keep happening or, more particularly, how to resolve it either via feeding Sequel proper settings (perhaps I have a malformed arg list) or modifying MySQL's /etc/my.cnf for such a scenario?
The Sequel jdbc adapter passes the connection string directly to JDBC, it doesn't parse out embedded options. You need to do:
DB = Sequel.connect("jdbc:mysql://localhost/project_db?user=USERNAME&password=PASSWD", :max_connections=>10, :pool_timeout=>120)
I don't know what causes it, but I have a Node app that keeps crashing. The console says Segmentation Fault, and it looks like it happens when two Mysql objects are instantiated (using db-mysql module), which becomes very common when 10+ users are using my site (I don't post the link to the app because I'm afraid the load would crash it ;) if it can be useful I'll post it).
Do you guys have any clue? My packages are up to date. Do you have a better package to use with Mysql (assuming it's where the problem lies)? Do you also encounter Segfault issues using Nodejs (I guess not, bcs stability is one of the main advantges of Node)?
I [think] I was definitely doing something wrong: cerating a new MySQL object and connecting to the DB every time I had a reaquest. Instead, I stored the MySQL object and run a single query for each... query. Working fine so far.