Reference
Entries by Title
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- How does fby work?
- What does it mean for a table to be a flipped dictionary?
- How do I execute a q function call with parameters over IPC?
- How do I use the functional forms of apply and amend?
- How do I use the functional form of @ (at) apply?
- How do I use the functional form of . (dot) apply?
- How does each-both (aka multivalent each) work?
- How can I capture STDOUT, STDERR and the exit status of a system command invoked from q?
- Why can't I index some elements of a dictionary?
- Why does the type of null returned by a failed dictionary key lookup vary?
- When does : (amend) not modify its first argument?
- What is q's equivalent to sql's ORDER BY?
- How do I extract hours, minutes, or seconds from a time?
- How do I parse a date and time?
- How do I get the length of a list?
- select sum size from a large table unexpectedly returns a negative number. Why?
- Does the order of field constraints matter in the performance of a select query?
- How do I set a breakpoint inside a q function?
- How do I expose a subset of partitions and remove the rest from view?
- I have a very large file to uncompress. zip and gzip do not work!
- What exactly does column-oriented mean?
- How do I convert a character to its ASCII code?
- I'm in a hurry. Can multiple kdb processes write simultaneously to a splayed database?
- How can I reorder column names of a splayed table on disk?
- How do I split a list?
- How can I find the data type of a given table column?
- How do I set the return value of a function?
- How can I test for the existence of a file or directory in q?
- How do I remove a key from a dictionary?
- I have a very big text file. Can I read a text file in chunks?
- How do I select all columns in q?
- How do I read in a text file?
- How do I convert from symbol to integer?
- How do I cast a string to a symbol?
- How do I parse a ctrl-A delimited string?
- How do I build a ctrl-A delimited string?
- How can I measure the performance of my q code?
- How do I declare a table column of type string (not symbol!)?
- Can a table be partitioned but not be splayed?
- What are some of the freely available software packages related to kdb?
- q truncates the results in stdout. How can I fix it?
- How do I use the timer?
- What environment variables do I need to know about when kdb starts up?
- I know k sits under q. By porting q code to k, will it run faster?
- I defined an untyped list, but I get a type error when I add more than one element to it? How do I store mixed data in a list?
- Does q have closures?
- Why doesn't 'select from tablename where name = `ABC/A' work?
- What does 'NUC mean?
- How do I save a table to delimited text?
- When I launch kdb with a directory, what exactly happens on start up and in what order?
- I wish to keep sym file small. How can I find out if I will be introducing a new symbol before splaying the data out to disk?
- How can I define my own infix functions?
- Why doesn’t my query 'select from reallybigtable' ever return?
- How do I store mixed data types in a single column of a table?
- How does kdb compare to cloud computing?
- How do I extract the milliseconds from a time?
- Can I simply invoke garbage collect and clear the root namespace instead of restarting the process to reinitialize my database?
- How portable is q code across operating systems?
- Given a value, how do I get the null of that value's type?
- What are 0!, 1! and 2!?
- How can I experiment on a production kdb while keeping the data free from accidental damage?
- What is a virtual column?
- What is the difference between the functions xcol and xcols?
- What should I know about the sym file, and why back it up?
- How do I get the day of the week?
- Is the output of meta available for use in my program?
- Who uses time series or column-oriented databases and why?
- How do I delete a function in namespace .z?
- How do I choose whether to make a field a symbol or string?
- How can I group all (other) columns?
- How can I slice a vector into a series of vectors of length n?
- Can I retrieve kdb data from my web browser and save the query results to a csv file for viewing in a spreadsheet?
- Is the q language simply syntactic sugar on top of k?
- I noticed a list with a `s# prefix attached. What does this mean?
- What does '\l .' or 'system “l ."' do?
- How do I comment q code?
- Can a historical database be partitioned on multiple levels - say, by date, then symbol?
- 'exit' fails to terminate kdb console. How do I gracefully exit a kdb process?
- How do i interpret the output of function .Q.w[]?
- I’ve setup many views based on a single large table. How much of a performance penalty will I pay?
- I want to keep kdb rdb super fast and prevent users from introducing large latencies by using a timeout argument of 2 seconds. is this a good idea?
- How do I efficiently retrieve the first n rows of a query result?
- How can I have kdb automatically load q code at startup in every session?
- How can I set a trigger on a kdb table?
- peach is great. Can I simply use it everywhere in place of each?
- How do I load in a csv file into kdb with the headers as table fieldnames?
- I’m purchasing new kdb server hardware. How should it be configured?
- What are the implicit, default argument names to a function?
- Why can’t kdb’s debugger tell me exactly which line in the function invoked the error?
- Why doesn't ‘\cd /fs/local/db;’ work?
- What companion tools to kdb are useful?
- How does 'protected execution' (or exception handling) work in q?
- How can I find a listing of tables in a given namespace?
- What is a dyadic function?
- I understand white space matters in q code. Where does it matter?
- How do I delete a column from a table?
- I know SQL and don’t care to learn q. Can I still get my work done while benefiting from kdb’s speed?
- How do I delete the nth row from a table?
- What does it mean for a q function or table to be a ‘first class’ type?
- What kdb connection libraries exist?
- What are some of the hard limits of kdb I should know about?
- Is q a purely functional language?
- Is function overloading supported in q?
- Why can’t I use exec on partitioned tables?
- What's the difference between kdb, kdb+, k, k4 and q?
- What does error output 'nyi mean?
- I know kdb is a in-memory database. my dataset is over two terabytes in size. However my RAM is limited to 32GB. How will this work?
- Can q script be compiled down to native code?
- Is polymorphism supported in q?
- How can I glue two tables side by side?
- How do I sort?
- What happens if I duplicate a partition name across multiple segments?
- Is there a free trial version of kdb available for download?
- I’m used to sprinkling print statements to debug my code. How can I do the same in q?
- How do I debug code in kdb?
- What data structures does q provide out of the box?
- Does q pass-by-value or pass-by-reference?
- Is it possible to hold partitioned table and unpartitioned table named the same on a single kdb process?
