I was able to implement a connection from R through RMariaDB and DBI to a remote MariaDB-database. However, I am currently encountering a strange change of numbers when querying the database through R. I'll explain the differences:
I inserted one simple entry in my database with the following command:
INSERT INTO respondent ( id, name ) VALUES ( 2388793051, 'testuser' )
When I connect to this database directly on the remote server and execute a statement like this:
SELECT * FROM respondent;
it delivers these value
id: 2388793051, name: testuser
So I should also be able to connect to the database via R and receive the same results. So when I execute the following code in R, I expect to receive this inserted and saved information displayed above:
library(DBI)
library(RMariaDB)
conn <- DBI::dbConnect(drv=RMariaDB::MariaDB(), user="myusername", password="mypassword", host="127.0.0.1", port="1111", dbname="mydbname")
res <- dbGetQuery(conn, "SELECT * FROM respondent")
print(res)
However, the result of this query is the following
id name
-1906174245 testuser
As you can see, the id is now -1906174245 instead of the saved 2388793051 in the database. I don't understand this weird conversion of integers in the id-field. Can someone explain how this problem emerges and how I might solve it?
EDIT: I don't expect this to be a problem, but just to inform you: I am using an SSH tunnel to enable a connection via these specified ports from my local to my remote machine.
SOLUTION: What made the difference was to specify the id of a respondent in the database specification already as BIGINT instead of INT. Thanks to #JonnyCrunch
Related
I'm trying to search in a database with python3 with PyMySQL. I want to have a list of ips, that can be put in a database and return that data to the ip address.
But i can't even search for one ip. Is it possible or not ?
ip = "10.0.4.64"
cur_syslog.execute("SELECT data FROM firewall WHERE source_ip = values (%s)",(ip))
Your query is not well written. It should be:
cur_syslog.execute("SELECT data FROM firewall WHERE source_ip = %s", (ip))
In SQL Server (i'm using 2008) is it possible to dynamically access server by server name?
My scenario: I have a production server, a development server, and a test server. Their structure is the same. There is a fourth server with some additional data - let's call it a data server.
On the data server there is a procedure. One of it's parameters is a name of the requesting server:
proc sp_myProcedure(#myId int, #serverName nvarchar(100))
The procedure accesses tables from the data server and from the requesting server. At the moment, to query the requesting server I'm using a case expression:
-- code on the data server
select additionalData = case #serverName
-- if the requesting server is production - query production
when 'ProdServer' then (select field1 from [ProdServer].[MyDataBase].[dbo].[MyTable] ...
-- if the requesting server is test - query test
when 'TestServer' then (select field1 from [TestServer].[MyDataBase].[dbo].[MyTable] ...
-- if the requesting server is development - query development
when 'DevServer' then (select field1 from [DevServer].[MyDataBase].[dbo].[MyTable] ...
end
My question is if there is any other way to access the requesting server. I'd like to replace ifs and cases with something more dynamic. Is it, for instance, possible to use the server name variable to dynamically access specific server. Something similar to the following (mocked) query:
declare myServer <server type> = Get_Server(#serverName)
-- the query
additionalData = select field1 from [myServer].[MyDataBase].[dbo].[MyTable]
I liked this approach
SELECT
SERVERPROPERTY('MachineName') AS [ServerName],
SERVERPROPERTY('ServerName') AS [ServerInstanceName],
SERVERPROPERTY('InstanceName') AS [Instance],
SERVERPROPERTY('Edition') AS [Edition],
SERVERPROPERTY('ProductVersion') AS [ProductVersion],
Left(##Version, Charindex('-', ##version) - 2) As VersionName
Link
Another approach which we were using was
Creating one database called database_yourprojectname
So, for the explanation I'm using database name as northwind
after that you can create one new database called northwind_db
Which has a following fields:
Servername,username(encrypted),password(encrypted),active
And then you can either make one page to insert/update/delete current database used there
or you can add statically data to it..so, you can use the database which is active currently.
Or use simple one:
SELECT ##SERVERNAME
Which is already stated here
I have a MySQL table that I am reading with the RMySQL package of R. I would like to be able to directly refer to the data frame stored in the table so I can seamlessly interact with it rather than having to execute RMySQL statement every time I want to do something. Is there a way to accomplish this? I tried:
data <- dbReadTable(conn = con, name = 'tablename')
For example, if I now want to check how many rows I have in this table I would run:
nrow(data)
Does this go through the database connection, or am I now storing the object "data" locally, defeating the whole purpose of using an external database?
data <- dbReadTable(conn = con, name = 'tablename')
This command downloads all the data into a local R dataframe (assuming you have enough RAM). Any operations with data from that point forward do not require the SQL connection.
I am trying to query my mysql database. I am using the database cookbook and can setup a connection with my database. I trying to query my database for information so now the question is how do I store than information so I can access it in another resource. Where do the results of the query get stored? This is my recipe:
mysql_database "Get admin users" do
connection mysql_connection_info
sql "Select * from #{table_name}"
action :query
end
Thanks in advance
If you don't have experience with Ruby, this might be really confusing. There's no way to "return" the result of a provider from a Chef resource. The mysql_database is a Chef::Recipe DSL method that gets translated to Chef::Provider::Database::Mysql at runtime. This provider is defined in the cookbook.
If you take some time to dive into that provider, you'll can see how it executes queries, using the db object. In order to get the results of a query, you'll need to create your own connection object in the recipe and execute a command against it. For example
require 'mysql'
db = ::Mysql.new('host', 'username', 'password', nil, 'port', 'socket') # varies with setup
users = db.query('SELECT * FROM users')
#
# You might need to manipulate the result into a more manageable data
# structure by splitting on a carriage return, etc...
#
# Assume the new object is an Array where each entry is a username.
#
file '/etc/group' do
contents users.join("\n")
end
I find using good old Chef::Mixin:ShellOut / shell_out() fairly sufficient for this job and it's DB agnostic (assuming you know your SQL :) ). It works particularly well if all you are querying is one value; for multiple rows/columns you will need to parse the SQL query results. You need to hide row counts, column headers, eat preceding white-space, etc. from your result set to just get the query results you want. For example, below works on SQL Server :
Single item
so = shell_out!("sqlcmd ... -Q \"set nocount on; select file_name(1)\" -h-1 -W")
db_logical_name = so.stdout.chop
Multiple rows/columns (0-based position of a value within a row tells you what this column is)
so = shell_out!("sqlcmd ... -Q \"set nocount on; select * from my_table\" -h-1 -W")
rows_column_data = so.stdout.chop
# columns within rows are space separated, so can be easily parsed
SELECT `aversio`.`module`.`module` AS `module`
FROM
`projectmodule`
JOIN `module` ON `aversio`.`projectmodule`.`moduleID` = `aversio`.`module`.`moduleID`
JOIN `project` ON `aversio`.`project`.`projectID` = `aversio`.`projectmodule`.`projectID`
WHERE `aversio`.`module`.`actief` = _utf8'1'
AND `aversio`.`projectmodule`.`verwijderd` = _utf8'0'
AND `aversio`.`projectmodule`.`verwijderd` = _utf8'0'
MYSQL Error : There is no 'aversio'#'%' registered
What this error mean
That actually looks like a permissions issue, like you are trying to connect as aversio to a MySQL server instance which is not configured to allow that user from any (%) domain.
The syntax 'aversio'#'%' looks like the format 'username'#'host', and mysql uses % as the catch-all (any) host wildcard.
Make sure that you create the MySQL user named aversio, and give them the correct permissions on your DB.
EDIT:
IIRC, a user of that name may exist, but with a different domain (i.e. the users table is keyed on the combo of user and host. I've seen this kind of thing happen when I move code from a dev server to a staging server and try to connect fro mthe new host, having forgotten to modify the permissions in MySQL.