The app I have is using intarray extension of the PostgreSQL.
Unfortunately it doesn't seem to be available according to the docs and the command line:
> echo 'show extwlist.extensions' | heroku pg:psql
extwlist.extensions
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
btree_gist,chkpass,cube,dblink,dict_int,dict_xsyn,earthdistance,fuzzystrmatch,hstore,isn,ltree,pg_trgm,pgcrypto,pgrowlocks,pgstattuple,plpgsql,unaccent,uuid-ossp,citext,tablefunc
(1 row)
Also:
> heroku pg:psql
psql (9.1.5, server 9.1.6)
SSL connection
Type "help" for help.
=> CREATE EXTENSION intarray;
WARNING: extension "intarray" is not whitelisted
CREATE EXTENSION
So does it mean I can't use Heroku or there IS a way to add intarray extension (using idx function for example).
Thanks.
The general consensus from the Postgres community I got was that intarray is obsoleted by just using int[] and that it's only kept around for backwards compatibility for very old applications. That's why we haven't added support for it.
So far everyone who asked for it was actually happier with int[] and just hadn't found it. Is there some usecase where you actually want an intarray column instead? We can just turn it on.
intarray has been whitelisted on Heroku since March 2014, so you should be able to enable the extension directly. If you provisioned your database before that you will first need to upgrade your database.
Have to answer my own question just to provide a little bit more details.
The intarray was used for extracting path information from columns containing strings like 123/312/56/9863. That was stored (poorly) as string instead of an array in the first place.
The reason we needed intarray is because we it had the idx function.
What was happening is this:
convert string to an array
find the given number using the idx
return the next number in sequence.
All that was done as a temporary measure. But since heroku couldn't support idx the only way to use it was by adding a custom function.
But instead we converted the queries and data structure to to use ltree and its index function.
Apart from not needing a dependency on idx (but introducing another dependency on ltree), we also improved the performance of the queries by a factor of x200.
Related
In Filemaker, is there a function or a way, perhaps a Get function, that can determine whether this is being viewed as a WebDirect or not? This way I can alternate some incompatible controls such as printing and saving as a PDF.
As #michael.hor257k pointed out, Get ( SystemPlatform ) is the function you're interested in using.
I'll add that I usually have a custom function I call something like IsWebDirect that returns the following:
Get ( SystemPlatform ) = 4
Then I'm able to have self-commenting calculations, such as If [ IsWebDirect ]. Obviously, I create similar custom functions for IsDesktop, IsMobile, etc.
I published a standard library of such functions (and many more) on GitHub, if you're interested.
I'm working on a fork of the RSQLServer package and am trying to implement joins. With the current version of the package, joins for any DBI-connected database are implemented using sql_join.DBIConnection. However, that implementation doesn't work well for SQL server. For instance, it makes use of USING which is not supported by SQL server.
I've got a version of this function sql_join.SQLServerConnection working (though not complete yet). I've based my function on sql_join.DBIConnection as much as possible. One issue I've had is that sql_join.DBIConnection calls a number of non-exported functions within dplyr such as common_by. For now, I've worked around this by using dplyr:::common_by, but I'm aware that that's not ideal practice.
Should I:
Ask Hadley Wickham/Romain Francois to export the relevant functions to make life easier for people developing packages that build on dplyr?
Copy the internal functions into the package I'm working on?
Continue to use the ::: operator to call the functions?
Something else?
Clearly with option 3, there's a chance that the interface will change (since they're not exported functions) and that the package would break in the longer term.
Sample code:
sql_join.SQLServerConnection <- function (con, x, y, type = "inner", by = NULL, ...) {
join <- switch(type, left = sql("LEFT"), inner = sql("INNER"),
right = sql("RIGHT"), full = sql("FULL"), stop("Unknown join type:",
type, call. = FALSE))
by <- dplyr:::common_by(by, x, y)
using <- FALSE # all(by$x == by$y)
x_names <- dplyr:::auto_names(x$select)
y_names <- dplyr:::auto_names(y$select)
# more code
}
It looks to me like you may not have to use those functions verbs. Since dplyr now put it's database functionality in dbplyr, the relevant code is here. I don't see the use of auto_names or common_by there.
I strongly recommend following the steps in Creating New Backends after reading SQL Translation.
It may also be worth reviewing some other alternative backends, such as Hrbrmaster's sergeant package for Apache Drill using JDBC.
I want to make a case-insensitive index in Neo4j using Py2neo.
Read through the docs and googled a lot but didn't find anything. There seems to be this option in Java but not in Py2neo.
Please help!
You can pass configuration options into the GraphDatabaseService.get_or_create_index function as indicated here:
http://book.py2neo.org/en/latest/graphs_nodes_relationships/#py2neo.neo4j.GraphDatabaseService.get_or_create_index
These arguments are passed directly into the REST call as described here:
http://docs.neo4j.org/chunked/milestone/rest-api-indexes.html#rest-api-create-node-index-with-configuration
Hope this helps.
When using legacy indexes you can supply a configuration upon initial creation of the index. You have to set to_lower_case=true in combination with type=fulltext.
Schema indexes on the other hand do not yet support case insensitivity. As a workaround, introduce a copy of the respective property, e.g. name -> nameLower, which gets populated by the lowercase variant of that string. You could do something like this on existing datasets:
CREATE INDEX ON :Person(nameLower);
// --- use seperate transaction
MATCH (p:Person) set p.nameLower = lower(p.name); // maybe apply LIMITs for large amount of nodes
Your query string of course needs to use lower case:
MATCH (p:Person {nameLower:'john'}) RETURN p
Following conversion
SELECT to_tsvector('english', 'Google.com');
returns this:
'google.com':1
Why does TSearch2 engine didn't return something like this?
'google':2, 'com':1
Or how can i make the engine to return the exploded string as i wrote above?
I just need "Google.com" to be foundable by "google".
Unfortunately, there is no quick and easy solution.
Denis is correct in that the parser is recognizing it as a hostname, which is why it doesn't break it up.
There are 3 other things you can do, off the top of my head.
You can disable the host parsing in the database. See postgres documentation for details. E.g. something like ALTER TEXT SEARCH CONFIGURATION your_parser_config
DROP MAPPING FOR url, url_path
You can write your own custom dictionary.
You can pre-parse your data before it's inserted into the database in some manner (maybe splitting all domains before going into the database).
I had a similar issue to you last year and opted for solution (2), above.
My solution was to write a custom dictionary that splits words up on non-word characters. A custom dictionary is a lot easier & quicker to write than a new parser. You still have to write C tho :)
The dictionary I wrote would return something like 'www.facebook.com':4, 'com':3, 'facebook':2, 'www':1' for the 'www.facebook.com' domain (we had a unique-ish scenario, hence the 4 results instead of 3).
The trouble with a custom dictionary is that you will no longer get stemming (ie: www.books.com will come out as www, books and com). I believe there is some work (which may have been completed) to allow chaining of dictionaries which would solve this problem.
First off in case you're not aware, tsearch2 is deprecated in favor of the built-in functionality:
http://www.postgresql.org/docs/9/static/textsearch.html
As for your actual question, google.com gets recognized as a host by the parser:
http://www.postgresql.org/docs/9.0/static/textsearch-parsers.html
If you don't want this to occur, you'll need to pre-process your text accordingly (or use a custom parser).
LuaSQL, which seems to be the canonical library for most SQL database systems in Lua, doesn't seem to have any facilities for quoting/escaping values in queries. I'm writing an application that uses SQLite as a backend, and I'd love to use an interface like the one specified by Python's DB-API:
c.execute('select * from stocks where symbol=?', t)
but I'd even settle for something even dumber, like:
conn:execute("select * from stocks where symbol=" + luasql.sqlite.quote(t))
Are there any other Lua libraries that support quoting for SQLite? (LuaSQLite3 doesn't seem to.) Or am I missing something about LuaSQL? I'm worried about rolling my own solution (with regexes or something) and getting it wrong. Should I just write a wrapper for sqlite3_snprintf?
I haven't looked at LuaSQL in a while but last time I checked it didn't support it. I use Lua-Sqlite3.
require("sqlite3")
db = sqlite3.open_memory()
db:exec[[ CREATE TABLE tbl( first_name TEXT, last_name TEXT ); ]]
stmt = db:prepare[[ INSERT INTO tbl(first_name, last_name) VALUES(:first_name, :last_name) ]]
stmt:bind({first_name="hawkeye", last_name="pierce"}):exec()
stmt:bind({first_name="henry", last_name="blake"}):exec()
for r in db:rows("SELECT * FROM tbl") do
print(r.first_name,r.last_name)
end
LuaSQLite3 as well an any other low level binding to SQLite offers prepared statements with variable parameters; these use methods to bind values to the statement parameters. Since SQLite does not interpret the binding values, there is simply no possibility of an SQL injection. This is by far the safest (and best performing) approach.
uroc shows an example of using the bind methods with prepared statements.
By the way in Lua SQL there is an undocumented escape function for the sqlite3 driver in conn:escape where conn is a connection variable.
For example with the code
print ("con:escape works. test'test = "..con:escape("test'test"))
the result is:
con:escape works. test'test = test''test
I actually tried that to see what it'd do. Apparently there is also such a function for their postgres driver too. I found this by looking at the tests they had.
Hope this helps.