How do I display the result set of a postgres query using the pg gem only ? I want it to be in tabular form like it is in pgAdmin GUI tool. The code below does not help. The documentation is not clear, so I am unable to figure another way out. Please help !
require 'pg'
conn = PGconn.connect("db.corp.com", 5432, '', '', "schema", "user", "pass")
sql = 'select * from tbl limit 2'
res = conn.exec(sql)
res.each do |row|
row.each do |column|
end
end
gem list -
pg (0.9.0.pre156 x86-mswin32)
ruby - 1.8.7
Steps -
1. Get list of column names in result set (type PGResult).
2. Iterate each row(hash) of result set.
3. For each row (hash key)/columns found in step 1, find the column values (hash value).
Then print results as csv. I dont think this is efficient, but it gets the job done.
require 'pg'
conn = PGconn.connect("db.corp.com", 5432, '', '', "schema", "user", "pass")
sql = 'select * from tbl limit 2'
res = conn.exec(sql)
rows_count = res.num_tuples
column_names = res.fields
col_header = column_names.join(', ')
puts col_header
for i in 0..rows_count-1
row_hash = res[i]
row_arr = []
column_names.each do |col|
row_arr << row_hash[col]
end
row = row_arr.join(', ')
puts row
end
Related
I'm trying to read and parse an sqlite3 query in Ruby using the sqlite3 gem. This db already exists on my machine.
I'm opening the db with
db = SQLite3::Database.new "/path to/database.sqlite"
The I'm executing my particular query with
db.execute( "SELECT * FROM `ZSFNOTE` WHERE `ZTRASHED` LIKE '0'" ) do |row|
Now, based on my (limited) experience, I was hoping that this could be parsed like a JSON response, where I could call something like row["ZTITLE"]. However, those headers aren't available in my response, I can only get at what I'm looking for by guessing an integer, like row[19].
I know I'm not even scratching the surface of the sqlite3 gem, but couldn't find the answer to this in the docs. Any help would be much appreciated.
You can use #execute2 to get the headers.
require 'sqlite3'
db = SQLite3::Database.new(':memory:')
db.execute 'CREATE TABLE "examples" ("header" varchar(20), "value" integer(8))'
db.execute 'INSERT INTO examples(header, value) VALUES("example", 1)'
db.execute2('select * from examples')
# => [["header", "value"], ["example", 1]]
You can map the headers to the columns like so:
headers, *rows = db.execute2('select * from examples')
rows.map! do |row|
row.each_with_index.with_object({}) do |(col, i), o|
o[headers[i]] = col
end
end
rows.each do |row|
p row['header']
end
# => "example"
You know certainly about .mode column & headers on, to show datas of a sqlite database. But how to obtain the same result wth in Ruby script?
For example, to add it to my own script:
begin
require 'sqlite3'
db = SQLite3::Database.open('test_albums.db')
db.execute("select * from albums where ecoute = 2") do |result|
puts result.join(' - ')
end
end
Very thanks!
You need to get the table info using pragma table_info(), e.g.:
begin
require 'sqlite3'
db = SQLite3::Database.open('test_albums.db')
columns = db.execute("pragma table_info(albums)")
puts (columns.map { |c| c[1] }).join(' - ')
db.execute("select * from albums where ecoute = 2") do |result|
puts result.join(' - ')
end
end
I'm having an issue with Ruby SQLite. This is my code,
require 'socket'
require 'sqlite3'
server = TCPServer.open(1337)
DB = SQLite3::Database.new "./Tavern.db"
loop {
Thread.start(server.accept) do |client|
input = client.gets
input = input.gsub '\n', ''
input = input.split(' ')
case input[0]
when 'register'
stmt = DB.prepare "INSERT INTO Managers (name, job, location, busy)
VALUES (?, ?, ?, 0)"
stmt.bind_params input[1], input[2], client.addr[3]
stmt.execute
when 'request_job'
stmt = DB.prepare "SELECT * FROM Tasks WHERE job = ? AND assigned = 0"
stmt.bind_params input[1]
results = stmt.execute
puts results.next
end
end
}
Where input[1] = "test"
If stmt.bind_params input[1] is changed to stmt.bind_params "test", the sql query works, if it is left as is, it doesn't. I've checked to make absolutely sure that "test" and input[1] are equal with == and by using .bytes on both of them and manually comparing.
Any ideas on why this might be the case?
Have you tried using the stmt.bind_params( 15, "hello" ) style syntax as well?
I have had a similar problem. It turned out that the string I was using had a different encoding than the encoding that was required.
Check what input[1].encoding and "test".encoding yield! If they are different, use the force_encoding-method.
I would like to use the Google bigquery gem (https://rubygems.org/gems/bigquery) to create an Array of table names. So far, this is what I have written:
require 'json'
bqRepsonse = bq.tables('myDataSet')
bqRepsonseCleaned = bqRepsonse.to_s.gsub("=>", ":")
data = JSON.parse(bqRepsonseCleaned)
tableListing = []
data["tableID"]["type"].each do |item|
case item["type"]
when 'TABLE'
bqTableList << item["tableId"]
else
end
end
If I print bqResponse, I get this result:
[{"kind"=>"bigquery#table",
"id"=>"curious-idea-532:dataset_test_4.TableA",
"tableReference"=>{"projectId"=>"curious-idea-532",
"datasetId"=>"dataset_test_4", "tableId"=>"TableA"}, "type"=>"TABLE"},
{"kind"=>"bigquery#table",
"id"=>"curious-idea-532:dataset_test_4.TableB",
"tableReference"=>{"projectId"=>"curious-idea-532",
"datasetId"=>"dataset_test_4", "tableId"=>"TableB"}, "type"=>"TABLE"},
{"kind"=>"bigquery#table",
"id"=>"curious-idea-532:dataset_test_4.TableC",
"tableReference"=>{"projectId"=>"curious-idea-532",
"datasetId"=>"dataset_test_4", "tableId"=>"TableC"}, "type"=>"TABLE"},
{"kind"=>"bigquery#table",
"id"=>"curious-idea-532:dataset_test_4.TableD",
"tableReference"=>{"projectId"=>"curious-idea-532",
"datasetId"=>"dataset_test_4", "tableId"=>"TableD"}, "type"=>"TABLE"}]
And running the code throws and error
`[]': no implicit conversion of String into Integer (TypeError)
Not sure where to correct this. My desired outcome is:
tableListing = ["TableA","TableB","TableC","TableD"]
Thanks in advance for your advice.
Try this:
require 'json'
string = '[{"kind": "bigquery#table", "id": "curious-idea-532:dataset_test_4.TableA", "tableReference" : {"projectId":"curious-idea-532", "datasetId":"dataset_test_4", "tableId":"TableA"}, "type":"TABLE"}, {"kind":"bigquery#table", "id":"curious-idea-532:dataset_test_4.TableB", "tableReference":{"projectId":"curious-idea-532", "datasetId":"dataset_test_4", "tableId":"TableB"}, "type":"TABLE"}, {"kind":"bigquery#table", "id":"curious-idea-532:dataset_test_4.TableC", "tableReference":{"projectId":"curious-idea-532", "datasetId":"dataset_test_4", "tableId":"TableC"}, "type":"TABLE"}, {"kind":"bigquery#table", "id":"curious-idea-532:dataset_test_4.TableD", "tableReference":{"projectId":"curious-idea-532", "datasetId":"dataset_test_4", "tableId":"TableD"}, "type":"TABLE"}]'
data = JSON.parse(string)
tableListing = []
# Here we are iterating over the data instead of its child element
data.each do |item|
case item["type"]
when 'TABLE'
tableListing << item["tableReference"]["tableId"]
else
end
end
puts tableListing
I have coded an app in ruby which queries the youtube website for some keywords which are taken from a specific db. After the youtube query is done the resulted videos' id and title are inserted into 2 different dbs. I have run the code and I got this exception:
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/sqlite3-1.3.8-x86-mingw32/lib/sqlite3/database.rb:91:in `initialize': near "'tag:youtube.com,2008:video:3taEuL4EHAg'": syntax error (SQLite3::SQLException)
Is this error caused by invalid characters in my queries? Should the SQLite gem that I used handle these?
If you need the code here it is:
require "sqlite3"
require "youtube_it"
database = SQLite3::Database.new("data.db")
client = YouTubeIt::Client.new(:dev_key =>"myyoutubekey")
result = database.query("SELECT `keyphrase` FROM `keyphrases`")
result.each do |array|
array.each do |result|
results = client.videos_by(:query => "#{result}", :page => 1, :per_page => 10)
results.videos.each do |videoone|
database.query("INSERT OR IGNORE INTO `videos` (videoID,cachedTitle) VALUES ('#{videoone.video_id}','videoone.title')")
rezultat = database.query("SELECT `id` FROM `keyphrases` WHERE `keyphrase` = '#{result}' ")
rezultat.each do |n|
id = n.to_s.delete("[").delete("]").to_i
database.query("INSERT INTO `keyphrase2videos` (keyphraseID,videoID) VALUES ('#{id}','#{videoone.video_id}'")
end
end
end
end
p "Recored Entered"
I was missing a " ) " in the VALUES clause