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  • table design for storing large number of rows

    - by hyperboreean
    I am trying to store in a postgresql database some unique identifiers along with the site they have been seen on. I can't really decide which of the following 3 option to choose in order to be faster and easy maintainable. The table would have to provide the following information: the unique identifier which unfortunately it's text the sites on which that unique identifier has been seen The amount of data that would have to hold is rather large: there are around 22 millions unique identifiers that I know of. So I thought about the following designs of the table: id - integer identifier - text seen_on_site - an integer, foreign key to a sites table This approach would require around 22 mil multiplied by the number of sites. id - integer identifier - text seen_on_site_1 - boolean seen_on_site_2 - boolean ............ seen_on_site_n - boolean Hopefully the number of sites won't go past 10. This would require only the number of unique identifiers that I know of, that is around 20 millions, but it would make it hard to work with it from an ORM perspective. one table that would store only unique identifiers, like in: id - integer unique_identifier - text, one table that would store only sites, like in: id - integer site - text and one many to many relation, like: id - integer, unique_id - integer (fk to the table storing identifiers) site_id - integer (fk to sites table) another approach would be to have a table that stores unique identifiers for each site So, which one seems like a better approach to take on the long run?

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  • SQLAlchemy Expression Language problem

    - by Torkel
    I'm trying to convert this to something sqlalchemy expression language compatible, I don't know if it's possible out of box and are hoping someone more experienced can help me along. The backend is PostgreSQL and if I can't make it as an expression I'll create a string instead. SELECT DISTINCT date_trunc('month', x.x) as date, COALESCE(b.res1, 0) AS res1, COALESCE(b.res2, 0) AS res2 FROM generate_series( date_trunc('year', now() - interval '1 years'), date_trunc('year', now() + interval '1 years'), interval '1 months' ) AS x LEFT OUTER JOIN( SELECT date_trunc('month', access_datetime) AS when, count(NULLIF(resource_id != 1, TRUE)) AS res1, count(NULLIF(resource_id != 2, TRUE)) AS res2 FROM tracking_entries GROUP BY date_trunc('month', access_datetime) ) AS b ON (date_trunc('month', x.x) = b.when) First of all I got a class TrackingEntry mapped to tracking_entries, the select statement within the outer joined can be converted to something like (pseudocode):: from sqlalchemy.sql import func, select from datetime import datetime, timedelta stmt = select([ func.date_trunc('month', TrackingEntry.resource_id).label('when'), func.count(func.nullif(TrackingEntry.resource_id != 1, True)).label('res1'), func.count(func.nullif(TrackingEntry.resource_id != 2, True)).label('res2') ], group_by=[func.date_trunc('month', TrackingEntry.access_datetime), ]) Considering the outer select statement I have no idea how to build it, my guess is something like: outer = select([ func.distinct(func.date_trunc('month', ?)).label('date'), func.coalesce(?.res1, 0).label('res1'), func.coalesce(?.res2, 0).label('res2') ], from_obj=[ func.generate_series( datetime.now(), datetime.now() + timedelta(days=365), timedelta(days=1) ).label(x) ]) Then I suppose I have to link those statements together without using foreign keys: outer.outerjoin(stmt???).??(func.date_trunc('month', ?.?), ?.when) Anyone got any suggestions or even better a solution?

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  • Django IntegrityError: foreign key violation upon delete

    - by Lukasz Korzybski
    I have Order and Shipment model. Shipment has a foreign key to Order. class Order(...): ... class Shipment() order = m.ForeignKey('Order') ... Now in one of my views I want do delete order object along with all related objects. So I invoke order.delete(). I have Django 1.0.4, PostgreSQL 8.4 and I use transaction middleware, so whole request is enclosed in single transaction. The problem is that upon order.delete() I get: ... File "/usr/local/lib/python2.6/dist-packages/django/db/backends/__init__.py", line 28, in _commit return self.connection.commit() IntegrityError: update or delete on table "main_order" violates foreign key constraint "main_shipment_order_id_fkey" on table "main_shipment" DETAIL: Key (id)=(45) is still referenced from table "main_shipment". I checked in connection.queries that proper queries are executed in proper order. First shipment is deleted, after that django executes delete on order row: {'time': '0.000', 'sql': 'DELETE FROM "main_shipment" WHERE "id" IN (17)'}, {'time': '0.000', 'sql': 'DELETE FROM "main_order" WHERE "id" IN (45)'} Foreign key have ON DELETE NO ACTION (default) and is initially deferred. I don't know why I get foreign key constraint violation. I also tried to register pre_delete signal and manually delete shipment objects before delete on order is called, but it resulted in the same error. I can change ON DELETE behaviour for this key in Postgres but it would be just a hack, I wonder if anyone has a better idea what's going on here. There is also a small detail, my Order model inherits from Cart model, so it actually doesn't have id field but cart_ptr_id and after DELETE on order is executed there is also DELETE on cart, but it seems unrelated? to the shipment-order problem so I simplified it in the example.

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  • For a set of sql-queries, how do you determine which result-set contains a certain row?

    - by ManBugra
    I have a set of sql - queries: List<String> queries = ... queries[0] = "select id from person where ..."; ... queries[8756] = "select id from person where ..."; Each query selects rows from the same table 'person'. The only difference is the where-clause. Table 'person' looks like this: id | name | ... many other columns How can i determine which queries will contain a certain person in their subset? For example: List<Integer> matchingQueries = magicMethod(queries, [23,45]); The list obtained by 'magicMethod' filters all sql queries present in the list 'queries' (defined above) and returns only those that contain either the person with id 23 OR a person with id 45. Why i need it: I am dealing with an application that contains products and categories where the categories are sql queries that define which products belong to them (queries stored in a table also). Now i have a requirement where an admin has to see all categories an item belongs to immediately after the item was created. Btw, over 8.000 categories defined (so far, more to come). language and db: java && postgreSQL Thanks,

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  • How to write this snippet in Python?

    - by morpheous
    I am learning Python (I have a C/C++ background). I need to write something practical in Python though, whilst learning. I have the following pseudocode (my first attempt at writing a Python script, since reading about Python yesterday). Hopefully, the snippet details the logic of what I want to do. BTW I am using python 2.6 on Ubuntu Karmic. Assume the script is invoked as: script_name.py directory_path import csv, sys, os, glob # Can I declare that the function accepts a dictionary as first arg? def getItemValue(item, key, defval) return !item.haskey(key) ? defval : item[key] dirname = sys.argv[1] # declare some default values here weight, is_male, default_city_id = 100, true, 1 # fetch some data from a database table into a nested dictionary, indexed by a string curr_dict = load_dict_from_db('foo') #iterate through all the files matching *.csv in the specified folder for infile in glob.glob( os.path.join(dirname, '*.csv') ): #get the file name (without the '.csv' extension) code = infile[0:-4] # open file, and iterate through the rows of the current file (a CSV file) f = open(infile, 'rt') try: reader = csv.reader(f) for row in reader: #lookup the id for the code in the dictionary id = curr_dict[code]['id'] name = row['name'] address1 = row['address1'] address2 = row['address2'] city_id = getItemValue(row, 'city_id', default_city_id) # insert row to database table finally: f.close() I have the following questions: Is the code written in a Pythonic enough way (is there a better way of implementing it)? Given a table with a schema like shown below, how may I write a Python function that fetches data from the table and returns is in a dictionary indexed by string (name). How can I insert the row data into the table (actually I would like to use a transaction if possible, and commit just before the file is closed) Table schema: create table demo (id int, name varchar(32), weight float, city_id int); BTW, my backend database is postgreSQL

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  • How to return a record from function executed by INSERT/UPDATE rule?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • How to return a record from function, executed by INSERT/UPDATE rule (trigger)?

    - by seas
    Do the following scheme for my database: create sequence data_sequence; create table data_table { id integer primary key; field varchar(100); }; create view data_view as select id, field from data_table; create function data_insert(_new data_view) returns data_view as $$declare _id integer; _result data_view%rowtype; begin _id := nextval('data_sequence'); insert into data_table(id, field) values(_id, _new.field); select * into _result from data_view where id = _id; return _result; end; $$ language plpgsql; create rule insert as on insert to data_view do instead select data_insert(new); Then type in psql: insert into data_view(field) values('abc'); Would like to see something like: id | field ----+--------- 1 | abc Instead see: data_insert ------------- (1, "abc") Is it possible to fix this somehow? Thanks for any ideas. Ultimate idea is to use this in other functions, so that I could obtain id of just inserted record without selecting for it from scratch. Something like: insert into data_view(field) values('abc') returning id into my_variable would be nice but doesn't work with error: ERROR: cannot perform INSERT RETURNING on relation "data_view" HINT: You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause. I don't really understand that HINT. I use PostgreSQL 8.4.

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  • Aggregating a list of dates to start and end date

    - by Joe Mako
    I have a list of dates and IDs, and I would like to roll them up into periods of consucitutive dates, within each ID. For a table with the columns "testid" and "pulldate" in a table called "data": | A79 | 2010-06-02 | | A79 | 2010-06-03 | | A79 | 2010-06-04 | | B72 | 2010-04-22 | | B72 | 2010-06-03 | | B72 | 2010-06-04 | | C94 | 2010-04-09 | | C94 | 2010-04-10 | | C94 | 2010-04-11 | | C94 | 2010-04-12 | | C94 | 2010-04-13 | | C94 | 2010-04-14 | | C94 | 2010-06-02 | | C94 | 2010-06-03 | | C94 | 2010-06-04 | I want to generate a table with the columns "testid", "group", "start_date", "end_date": | A79 | 1 | 2010-06-02 | 2010-06-04 | | B72 | 2 | 2010-04-22 | 2010-04-22 | | B72 | 3 | 2010-06-03 | 2010-06-04 | | C94 | 4 | 2010-04-09 | 2010-04-14 | | C94 | 5 | 2010-06-02 | 2010-06-04 | This is the the code I came up with: SELECT t2.testid, t2.group, MIN(t2.pulldate) AS start_date, MAX(t2.pulldate) AS end_date FROM(SELECT t1.pulldate, t1.testid, SUM(t1.check) OVER (ORDER BY t1.testid,t1.pulldate) AS group FROM(SELECT data.pulldate, data.testid, CASE WHEN data.testid=LAG(data.testid,1) OVER (ORDER BY data.testid,data.pulldate) AND data.pulldate=date (LAG(data.pulldate,1) OVER (PARTITION BY data.testid ORDER BY data.pulldate)) + integer '1' THEN 0 ELSE 1 END AS check FROM data ORDER BY data.testid, data.pulldate) AS t1) AS t2 GROUP BY t2.testid,t2.group ORDER BY t2.group; I use the use the LAG windowing function to compare each row to the previous, putting a 1 if I need to increment to start a new group, I then do a running sum of that column, and then aggregate to the combinations of "group" and "testid". Is there a better way to accomplish my goal, or does this operation have a name? I am using PostgreSQL 8.4

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  • Error using to_char // to_timetamp

    - by pepersview
    Hello, I have a database in PostgreSQL and I'm developing an application in PHP using this database. The problem is that when I execute the following query I get a nice result in phpPgAdmin but in my PHP application I get an error. The query: SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('2010-4-12', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '2010-4-12') ORDER BY t.t_name ASC And this is the error in PHP operator does not exist: text = integer (to_timestamp('', 'YYYY-MM-DD'),'FMD') = (courset... ^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts. The purpose to solve this error is to use the ORIGINAL query in php with : $date = "2010"."-".$selected_month."-".$selected_day; SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('$date', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '$date') ORDER BY t.t_name ASC

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  • Getting the last element of a Postgres array, declaratively

    - by Wojciech Kaczmarek
    How to obtain the last element of the array in Postgres? I need to do it declaratively as I want to use it as a ORDER BY criteria. I wouldn't want to create a special PGSQL function for it, the less changes to the database the better in this case. In fact, what I want to do is to sort by the last word of a specific column containing multiple words. Changing the model is not an option here. In other words, I want to push Ruby's sort_by {|x| x.split[-1]} into the database level. I can split a value into array of words with Postgres string_to_array or regexp_split_to_array functions, then how to get its last element?

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  • calculating change (over a period) for a dated field

    - by morpheous
    I have two tables with the following schema: CREATE TABLE sales_data ( sales_time date NOT NULL, product_id integer NOT NULL, sales_amt double NOT NULL ); CREATE TABLE date_dimension ( id integer NOT NULL, datestamp date NOT NULL, day_part integer NOT NULL, week_part integer NOT NULL, month_part integer NOT NULL, qtr_part integer NOT NULL, year_part integer NOT NULL, ); I want to write two types of queries that will allow me to calculate: period on period change (e.g. week on week change) change in period on period change (e.g. change in week on week change) I would prefer to write this in ANSI SQL, since I dont want to be tied to any particular db. [Edit] In light of some of the comments, if I have to be tied to a single database (in terms of SQL dialect), it will have to be PostgreSQL The queries I want to write are of the form (pseudo SQL of course): Query Type 1 (Period on Period Change) ======================================= a). select product_id, ((sd2.sales_amt - sd1.sales_amt)/sd1.sales_amt) as week_on_week_change from sales_data sd1, sales_data sd2, date_dimension dd where {SOME CRITERIA) b). select product_id, ((sd2.sales_amt - sd1.sales_amt)/sd1.sales_amt) as month_on_month_change from sales_data sd1, sales_data sd2, date_dimension dd where {SOME CRITERIA) Query Type 2 (Change in Period on Period Change) ================================================= a). select product_id, ((a2.week_on_week_change - a1.week_on_week_change)/a1.week_on_week_change) as change_on_week_on_week_change from (select product_id, ((sd2.sales_amt - sd1.sales_amt)/sd1.sales_amt) as week_on_week_change from sales_data sd1, sales_data sd2, date_dimension dd where {SOME CRITERIA) as a1), (select product_id, ((sd2.sales_amt - sd1.sales_amt)/sd1.sales_amt) as week_on_week_change from sales_data sd1, sales_data sd2, date_dimension dd where {SOME CRITERIA) as a2) WHERE {SOME OTHER CRITERIA}

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  • Grouping by date, with 0 when count() yields no lines

    - by SCO
    I'm using Postgresql 9 and I'm fighting with counting and grouping when no lines are counted. Let's assume the following schema : create table views { date_event timestamp with time zone ; event_id integer; } Let's imagine the following content : 2012-01-01 00:00:05 2 2012-01-01 01:00:05 5 2012-01-01 03:00:05 8 2012-01-01 03:00:15 20 I want to group by hour, and count the number of lines. I wish I could retrieve the following : 2012-01-01 00:00:00 1 2012-01-01 01:00:00 1 2012-01-01 02:00:00 0 2012-01-01 03:00:00 2 2012-01-01 04:00:00 0 2012-01-01 05:00:00 0 . . 2012-01-07 23:00:00 0 I mean that for each time range slot, I count the number of lines in my table whose date correspond, otherwise, I return a line with a count at zero. The following will definitely not work (will yeld only lines with counted lines 0). SELECT extract ( hour from date_event ),count(*) FROM views where date_event > '2012-01-01' and date_event <'2012-01-07' GROUP BY extract ( hour from date_event ); Please note I might also need to group by minute, or by hour, or by day, or by month, or by year (multiple queries is possible of course). I can only use plain old sql, and since my views table can be very big (100M records), I try to keep performance in mind. How can this be achieved ? Thank you !

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  • C# and NpgsqlDataAdapter returning a single string instead of a data table

    - by tme321
    I have a postgresql db and a C# application to access it. I'm having a strange error with values I return from a NpgsqlDataAdapter.Fill command into a DataSet. I've got this code: NpgsqlCommand n = new NpgsqlCommand(); n.Connection = connector; // a class member NpgsqlConnection DataSet ds = new DataSet(); DataTable dt = new DataTable(); // DBTablesRef are just constants declared for // the db table names and columns ArrayList cols = new ArrayList(); cols.Add(DBTablesRef.all); //all is just * ArrayList idCol = new ArrayList(); idCol.Add(DBTablesRef.revIssID); ArrayList idVal = new ArrayList(); idVal.Add(idNum); // a function parameter // Select builder and Where builder are just small // functions that return an sql statement based // on the parameters. n is passed to the where // builder because the builder uses named // parameters and sets them in the NpgsqlCommand // passed in String select = SelectBuilder(DBTablesRef.revTableName, cols) + WhereBuilder(n,idCol, idVal); n.CommandText = select; try { NpgsqlDataAdapter da = new NpgsqlDataAdapter(n); ds.Reset(); // filling DataSet with result from NpgsqlDataAdapter da.Fill(ds); // C# DataSet takes multiple tables, but only the first is used here dt = ds.Tables[0]; } catch (Exception e) { Console.WriteLine(e.ToString()); } So my problem is this: the above code works perfectly, just like I want it to. However, if instead of doing a select on all (*) if I try to name individual columns to return from the query I get the information I asked for, but rather than being split up into seperate entries in the data table I get a string in the first index of the data table that looked something like: "(0,5,false,Bob Smith,7)" And the data is correct, I would be expecting 0, then 5, then a boolean, then some text etc. But I would (obviously) prefer it to not be returned as just one big string. Anyone know why if I do a select on * I get a datatable as expected, but if I do a select on specific columns I get a data table with one entry that is the string of the values I'm asking for?

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  • Compiling ruby1.9.1 hangs and fills swap!

    - by nfm
    I'm compiling Ruby 1.9.1-p376 under Ubuntu 8.04 server LTS (64-bit), by doing the following: $ ./configure $ make $ sudo make install ./configure works without complaints. make hangs indefinitely until all my RAM and swap is gone. It get stuck after the following output: compiling ripper make[1]: Entering directory `/tmp/ruby1.9.1/ruby-1.9.1-p376/ext/ripper' gcc -I. -I../../.ext/include/x86_64-linux -I../.././include -I../.././ext/ripper -I../.. -I../../. -DRUBY_EXTCONF_H=\"extconf.h\" -fPIC -O2 -g -Wall -Wno-parentheses -o ripper.o -c ripper.c If I run the gcc command by hand, with the -v argument to get verbose output, it hangs after the following: Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu4) /usr/lib/gcc/x86_64-linux-gnu/4.2.4/cc1 -quiet -v -I. -I../../.ext/include/x86_64-linux -I../.././include -I../.././ext/ripper -I../.. -I../../. -DRUBY_EXTCONF_H="extconf.h" ripper.c -quiet -dumpbase ripper.c -mtune=generic -auxbase-strip ripper.o -g -O2 -Wall -Wno-parentheses -version -fPIC -fstack-protector -fstack-protector -o /tmp/ccRzHvYH.s ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu" ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/4.2.4/../../../../x86_64-linux-gnu/include" ignoring nonexistent directory "/usr/include/x86_64-linux-gnu" ignoring duplicate directory "../.././ext/ripper" ignoring duplicate directory "../../." #include "..." search starts here: #include <...> search starts here: . ../../.ext/include/x86_64-linux ../.././include ../.. /usr/local/include /usr/lib/gcc/x86_64-linux-gnu/4.2.4/include /usr/include End of search list. GNU C version 4.2.4 (Ubuntu 4.2.4-1ubuntu4) (x86_64-linux-gnu) compiled by GNU C version 4.2.4 (Ubuntu 4.2.4-1ubuntu4). GGC heuristics: --param ggc-min-expand=47 --param ggc-min-heapsize=32795 Compiler executable checksum: 6e11fa7ca85fc28646173a91f2be2ea3 I just compiled ruby on another computer for reference, and it took about 10 seconds to print the following output (after the above Compiler executable checksum line): COLLECT_GCC_OPTIONS='-v' '-I.' '-I../../.ext/include/i686-linux' '-I../.././include' '-I../.././ext/ripper' '-I../..' '-I../../.' '-DRUBY_EXTCONF_H="extconf.h"' '-D_FILE_OFFSET_BITS=64' '-fPIC' '-O2' '-g' '-Wall' '-Wno-parentheses' '-o' 'ripper.o' '-c' '-mtune=generic' '-march=i486' as -V -Qy -o ripper.o /tmp/cca4fa7R.s GNU assembler version 2.20 (i486-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.20 COMPILER_PATH=/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/ LIBRARY_PATH=/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/4.4.1/:/usr/lib/gcc/i486-linux-gnu/4.4.1/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/i486-linux-gnu/4.4.1/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-I.' '-I../../.ext/include/i686-linux' '-I../.././include' '-I../.././ext/ripper' '-I../..' '-I../../.' '-DRUBY_EXTCONF_H="extconf.h"' '-D_FILE_OFFSET_BITS=64' '-fPIC' '-O2' '-g' '-Wall' '-Wno-parentheses' '-o' 'ripper.o' '-c' '-mtune=generic' '-march=i486' I have absolutely no clue what could be going wrong here - any ideas where I should start?

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  • How do I add a column that displays the number of distinct rows to this query?

    - by Fake Code Monkey Rashid
    Hello good people! I don't know how to ask my question clearly so I'll just show you the money. To start with, here's a sample table: CREATE TABLE sandbox ( id integer NOT NULL, callsign text NOT NULL, this text NOT NULL, that text NOT NULL, "timestamp" timestamp with time zone DEFAULT now() NOT NULL ); CREATE SEQUENCE sandbox_id_seq START WITH 1 INCREMENT BY 1 NO MINVALUE NO MAXVALUE CACHE 1; ALTER SEQUENCE sandbox_id_seq OWNED BY sandbox.id; SELECT pg_catalog.setval('sandbox_id_seq', 14, true); ALTER TABLE sandbox ALTER COLUMN id SET DEFAULT nextval('sandbox_id_seq'::regclass); INSERT INTO sandbox VALUES (1, 'alpha', 'foo', 'qux', '2010-12-29 16:51:09.897579+00'); INSERT INTO sandbox VALUES (2, 'alpha', 'foo', 'qux', '2010-12-29 16:51:36.108867+00'); INSERT INTO sandbox VALUES (3, 'bravo', 'bar', 'quxx', '2010-12-29 16:52:36.370507+00'); INSERT INTO sandbox VALUES (4, 'bravo', 'foo', 'quxx', '2010-12-29 16:52:47.584663+00'); INSERT INTO sandbox VALUES (5, 'charlie', 'foo', 'corge', '2010-12-29 16:53:00.742356+00'); INSERT INTO sandbox VALUES (6, 'delta', 'foo', 'qux', '2010-12-29 16:53:10.884721+00'); INSERT INTO sandbox VALUES (7, 'alpha', 'foo', 'corge', '2010-12-29 16:53:21.242904+00'); INSERT INTO sandbox VALUES (8, 'alpha', 'bar', 'corge', '2010-12-29 16:54:33.318907+00'); INSERT INTO sandbox VALUES (9, 'alpha', 'baz', 'quxx', '2010-12-29 16:54:38.727095+00'); INSERT INTO sandbox VALUES (10, 'alpha', 'bar', 'qux', '2010-12-29 16:54:46.237294+00'); INSERT INTO sandbox VALUES (11, 'alpha', 'baz', 'qux', '2010-12-29 16:54:53.891606+00'); INSERT INTO sandbox VALUES (12, 'alpha', 'baz', 'corge', '2010-12-29 16:55:39.596076+00'); INSERT INTO sandbox VALUES (13, 'alpha', 'baz', 'corge', '2010-12-29 16:55:44.834019+00'); INSERT INTO sandbox VALUES (14, 'alpha', 'foo', 'qux', '2010-12-29 16:55:52.848792+00'); ALTER TABLE ONLY sandbox ADD CONSTRAINT sandbox_pkey PRIMARY KEY (id); Here's the current SQL query I have: SELECT * FROM ( SELECT DISTINCT ON (this, that) id, this, that, timestamp FROM sandbox WHERE callsign = 'alpha' AND CAST(timestamp AS date) = '2010-12-29' ) playground ORDER BY timestamp DESC This is the result it gives me: id this that timestamp ----------------------------------------------------- 14 foo qux 2010-12-29 16:55:52.848792+00 13 baz corge 2010-12-29 16:55:44.834019+00 11 baz qux 2010-12-29 16:54:53.891606+00 10 bar qux 2010-12-29 16:54:46.237294+00 9 baz quxx 2010-12-29 16:54:38.727095+00 8 bar corge 2010-12-29 16:54:33.318907+00 7 foo corge 2010-12-29 16:53:21.242904+00 This is what I want to see: id this that timestamp count ------------------------------------------------------------- 14 foo qux 2010-12-29 16:55:52.848792+00 3 13 baz corge 2010-12-29 16:55:44.834019+00 2 11 baz qux 2010-12-29 16:54:53.891606+00 1 10 bar qux 2010-12-29 16:54:46.237294+00 1 9 baz quxx 2010-12-29 16:54:38.727095+00 1 8 bar corge 2010-12-29 16:54:33.318907+00 1 7 foo corge 2010-12-29 16:53:21.242904+00 1 EDIT: I'm using PostgreSQL 9.0.* (if that helps any).

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  • Ruby gems gone after after jruby install

    - by James
    Today I installed jruby by downloading it, extracting it to /home/james/jruby-1.4.0 and adding the following line to .bashrc export JRUBY_HOME=/home/james/jruby-1.4.0 export PATH=$JRUBY_HOME/bin:$PATH And then I installed some jruby gems via jruby -S gem install ... Jruby works fine, but this seemed to have cause two problems: 1) When I try to run a ruby (not jruby) on rails migration, I see: Missing the Rails gem. Please `gem install -v= rails`, update your RAILS_GEM_VERSION setting in config/environment.rb for the Rails version you do have installed, or comment out RAILS_GEM_VERSION to use the latest version installed. 2) when I do gem list --local, I only see the gems that I've installed for jruby. Launching web applications via ruby script/server succeeds without any warnings. Please help.

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  • Using multiple aggregate functions in an algebraic expression in (ANSI) SQL statement

    - by morpheous
    I have the following aggregate functions (AGG FUNCs): foo(), foobar(), fredstats(), barneystats(). I want to know if I can use multiple AGG FUNCs in an algebraic expression. This may seem a strange/simplistic question for seasoned SQL developers - however, the but the reason I ask is that so far, all AGG FUNCs examples I have seen are of the simplistic variety e.g. max(salary) < 100, rather than using the AGG FUNCs in an expression which involves using multiple AGG FUNCs in an expression (like agg_func1() agg_func2()). The information below should help clarify further. Given tables with the following schemas: CREATE TABLE item (id int, length float, weight float); CREATE TABLE item_info (item_id, name varchar(32)); # Is it legal (ANSI) SQL to write queries of this format ? SELECT id, name, foo, foobar, fredstats FROM A, B (SELECT id, foo(123) as foo, foobar('red') as foobar, fredstats('weight') as fredstats FROM item GROUP BY id HAVING [ALGEBRAIC EXPRESSION] ORDER BY id AS A), item_info AS B WHERE item.id = B.id Where: ALGEBRAIC EXPRESSION is the type of expression that can be used in a WHERE clause - for example: ((foo(x) < foobar(y)) AND foobar(y) IN (1,2,3)) OR (fredstats(x) <> 0)) I am using PostgreSQL as the db, but I would prefer to use ANSI SQL wherever possible. Assuming it is legal to include AGG FUNCS in the way I have done above, I'd like to know: Is there a more efficient way to write the above query ? Is there any way I can speed up the query in terms of a judicious choice of indexes on the tables item and item_info ? Is there a performance hit of using AGG FUNCs in an algebraic expression like I am (i.e. an expression involving the output of aggregate functions rather than constants? Can the expression also include 'scaled' AGG FUNC? (for example: 2*foo(123) < -3*foobar(456) ) - will scaling (i.e. multiplying an AGG FUNC by a number have an effect on performance?) How can I write the query above using INNER JOINS instead?

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  • Prevent SQL Injection in Dynamic column names

    - by Mr Shoubs
    I can't get away without writing some dynamic sql conditions in a part of my system (using Postgres). My question is how best to avoid SQL Injection with the method I am currently using. EDIT (Reasoning): There are many of columns in a number of tables (a number which grows (only) and is maintained elsewhere). I need a method of allowing the user to decide which (predefined) column they want to query (and if necessary apply string functions to). The query itself is far too complex for the user to write themselves, nor do they have access to the db. There are 1000's of users with varying requirements and I need to remain as flexible as possible - I shouldn't have to revisit the code unless the main query needs to change - Also, there is no way of knowing what conditions the user will need to use. I have objects (received via web service) that generates a condition (the generation method is below - it isn't perfect yet) for some large sql queries. The _FieldName is user editable (parameter name was, but it didn't need to be) and I am worried it could be an attack vector. I put double quotes (see quoted identifier) around the field name in an attempt to sanitize the string, this way it can never be a key word. I could also look up the field name against a list of fields, but it would be difficult to maintain on a timely basis. Unfortunately the user must enter the condition criteria, I am sure there must be more I can add to the sanatize method? and does quoting the column name make it safe? (my limited testing seems to think so). an example built condition would be "AND upper(brandloaded.make) like 'O%' and upper(brandloaded.make) not like 'OTHERBRAND'" ... Any help or suggestions are appreciated. Public Function GetCondition() As String Dim sb As New Text.StringBuilder 'put quote around the table name in an attempt to prevent some sql injection 'http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html sb.AppendFormat(" {0} ""{1}"" ", _LogicOperator.ToString, _FieldName) Select Case _ConditionOperator Case ConditionOperatorOptions.Equals sb.Append(" = ") ... End Select sb.AppendFormat(" {0} ", Me.UniqueParameterName) 'for parameter Return Me.Sanitize(sb) End Function Private Function Sanitize(ByVal sb As Text.StringBuilder) As String 'compare against a similar blacklist mentioned here: http://forums.asp.net/t/1254125.aspx sb.Replace(";", "") sb.Replace("'", "") sb.Replace("\", "") sb.Replace(Chr(8), "") Return sb.ToString End Function Public ReadOnly Property UniqueParameterName() As String Get Return String.Concat(":" _UniqueIdentifier) End Get End Property

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  • Switching/Linking to another external stylesheet in a .js file using Ruby on Rails

    - by Jake
    Im learning JQuery from a Sitepoint Book but Im trying to apply all the lessons to a Rails App. In one lesson, we are taught how to switch to a different stylesheet if the browser window is resized beyond a certain point. Here's the javascript code: if ($('body').width() > 900) { $('<link rel="stylesheet" href="wide.css" type="text/css" />') .appendTo('head'); } else { $('link[href=wide.css]').remove(); } Rails doesn't seem to want to link to the new stylesheet using 'link rel'. I've tried using the Rails helper: <%= stylesheet_link_tag 'base', :media => 'screen' %> but that doesn't work in a .js file. How do I link to an external stylesheet in a .js file using Ruby? Can I use Ruby on Rails code in a .js file? Thanks.

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  • Rails: Auto-Detecting Database Adapter

    - by Dex
    The new version of the ar-extensions gem requires that you load the appropriate adapter yourself. On my development side I use mysql, however Heroku uses PostgreSQL. For example, on my development side I need to do this: require 'ar-extensions/adapters/mysql' require 'ar-extensions/import/mysql' How can I audo-detect which adapter to use?

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  • Store CSPC and UPC Codes in Rails

    - by Kevin Sylvestre
    What the best way to store CSPC and UPC codes are in Rails? I used integers with SQLite, but had overflow issues when moving to production. I've since switch to strings, but am not sure if a better generic datatype (needs to support SQLite, MySQL and PostgreSQL). Thanks.

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  • Creating application using rails 2.3.5 and cassandra database

    - by Joshi
    hi all, Pls guide me how to create rails application using rails 2.3.5 and cassandra database as rails 2.3.5 supports mysql, sqllite etc. I typed in the command prompt like this $ rails -d cassandra myapp Databases supported for preconfiguration are: mysql, oracle, postgresql, sqlite2, sqlite3, frontbase, ibm_db So pls help me in this regard

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  • Printing a variable only when it changes?

    - by user1781639
    First off, my question was a little vague or confusing since I'm not really sure how to phrase my question to be specific. I'm trying to query a database of stockists for a Knitting company (school project using PHP) but I'm looking to print the city as a heading instead of with each stockists information. Here is what I have at the moment: $sql = "SELECT * FROM mc16korustockists where locale = 'south'"; $result = pg_exec($sql); $nrows = pg_numrows($result); print $nrows; $items = pg_fetch_all($result); print_r($items); for ($i=0; $i<$nrows2; $i++) { print "<h2>"; print $items[$i]['city']; print "</h2>"; print $items[$i]['name']; print $items[$i]['address']; print $items[$i]['city']; print $items[$i]['phone']; print "<br />"; print "<br />"; } I'm querying the database for all of the data in it, the rows being ref, name, address, city and phone, and executing it. Querying the number of rows then using that to determine how many iterations for the loop to run is all fine but what I'd like to have is for the h2 heading to appear above the for ($i=0;) line. Trying just breaks my page so that might be out of the question. I figure I'd have to count the number of entries in 'city' until it detects a change then change the heading to that name I think? That or make a heap of queries and set a variable for each name but at point, I might as well do it manually (and I highly doubt it would be best practice). Oh, and I'd welcome any critiques to my PHP since I'm just starting out. Thanks and if you need any more information, just ask! P.S. Our class is learning with PostgreSQL instead of MySQL as you can see in the tags.

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