I can’t find a definite answer to this question in the documentation. If a column is an array type, will all the entered values be individually indexed? I created a simple table with one int[] column, and put a unique index on it. I noticed that I couldn’t add the same array of ints, which … Read more
I’m a little bit confused about how to get an index of a selected option from a HTML <select> item. On this page there are two methods described. However, both are always returning -1. Here is my jQuery code: $(document).ready(function(){ $(“#dropDownMenuKategorie”).change(function(){ alert($(“#dropDownMenuKategorie option:selected”).index()); alert($(“select[name=”dropDownMenuKategorie”] option:selected”).index()); }); }); and in html (…) <select id=”dropDownMenuKategorie”> <option value=”gastronomie”>Gastronomie</option> … Read more
I have a list: a = [32, 37, 28, 30, 37, 25, 27, 24, 35, 55, 23, 31, 55, 21, 40, 18, 50, 35, 41, 49, 37, 19, 40, 41, 31] max element is 55 (two elements on position 9 and 12) I need to find on which position(s) the maximum value is situated. Please, … Read more
Very simple example – one table, one index, one query: CREATE TABLE book ( id bigserial NOT NULL, “year” integer, — other columns… ); CREATE INDEX book_year_idx ON book (year) EXPLAIN SELECT * FROM book b WHERE b.year > 2009 gives me: Seq Scan on book b (cost=0.00..25663.80 rows=105425 width=622) Filter: (year > 2009) Why … Read more
I’ve heard that you should put columns that will be the most selective at the beginning of the index declaration. Example: CREATE NONCLUSTERED INDEX MyINDX on Table1 ( MostSelective, SecondMost, Least ) First off, is what I’m saying correct? If so, am i likely to see large differences in performance by rearranging the order of … Read more
Recently began branching out from my safe place (R) into Python and and am a bit confused by the cell localization/selection in Pandas. I’ve read the documentation but I’m struggling to understand the practical implications of the various localization/selection options. Is there a reason why I should ever use .loc or .iloc over at, and … Read more
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As I can understand documentation the following definitions are equivalent: create table foo ( id serial primary key, code integer, label text, constraint foo_uq unique (code, label)); create table foo ( id serial primary key, code integer, label text); create unique index foo_idx on foo using btree (code, label); However, a note in the manual … Read more
Can you create an index on a table variable in SQL Server 2000? i.e. DECLARE @TEMPTABLE TABLE ( [ID] [int] NOT NULL PRIMARY KEY ,[Name] [nvarchar] (255) COLLATE DATABASE_DEFAULT NULL ) Can I create an index on Name? 3 Answers 3
I have some troubles with an array. I have one array that I want to modify like below. I want to remove element (elements) of it by index and then re-index array. Is it possible? $foo = array( ‘whatever’, // [0] ‘foo’, // [1] ‘bar’ // [2] ); $foo2 = array( ‘foo’, // [0], before … Read more