If you have a UNIQUE INDEX then you don’t also need the INDEX – it would be redundant. A UNIQUE INDEX is both a unique constraint and an index that can be used like any other index. From the documentation: Note: The preferred way to add a unique constraint to a table is ALTER TABLE … Read more
If you want a dynamic index that doesn’t require any updating the only method I’ve found is by generating it client side with the github contents api. Here is a simple example that creates links to files in the top level directory of your project. If you want to support subdirectories using this method you … Read more
A very late reply, but it might be useful for somebody else later: *:* AND NOT country:sweden IF I’m not mistaken this should do a logical “AND” with all documents and the documents with a country that is different from “sweden”.
Probably one of the best explanations of SSTables and LSM-Trees for mortals is given by Martin Kleppmann in his “Designing Data-Intensive Applications” book. These data structures are explained in chapter 3, “Storage and Retrieval”, pages 69 through 79. It’s a really great read, I would recommend the whole book! Impatient ones could find my synopsis … Read more
df = pd.DataFrame([[‘Jhon’,15,’A’],[‘Anna’,19,’B’],[‘Paul’,25,’D’]]) df. columns = [‘Name’,’Age’,’Grade’] df Out[472]: Name Age Grade 0 Jhon 15 A 1 Anna 19 B 2 Paul 25 D You can get the index of your row: i = df[((df.Name == ‘jhon’) &( df.Age == 15) & (df.Grade == ‘A’))].index and then drop it: df.drop(i) Out[474]: Name Age Grade 1 … Read more
You can get_level_values in conjunction with Boolean slicing. In [50]: print df[np.in1d(df.index.get_level_values(1), [‘Lake’, ‘River’, ‘Upland’])] Area NSRCODE PBL_AWI CM Lake 57124.819333 River 1603.906642 LBH Lake 258046.508310 River 44262.807900 The same idea can be expressed in many different ways, such as df[df.index.get_level_values(‘PBL_AWI’).isin([‘Lake’, ‘River’, ‘Upland’])] Note that you have ‘upland’ in your data instead of ‘Upland’
>>> [“foo”, “bar”, “baz”].index(“bar”) 1 See the documentation for the built-in .index() method of the list: list.index(x[, start[, end]]) Return zero-based index in the list of the first item whose value is equal to x. Raises a ValueError if there is no such item. The optional arguments start and end are interpreted as in the … Read more
As you said some-word -> [doc385, doc211, doc39977, …] (sorted by rank, descending), I think the search engine may not do this, the doc list should be sorted by doc ID, each doc has a rank according to the word. When a query comes, it contains several keywords. For each word, you can find a … Read more
Super columns suffer from a number of problems, not least of which is that it is necessary for Cassandra to deserialze all of the sub-columns of a super column when querying (even if the result will only return a small subset). As a result, there is a practical limit to the number of sub-columns per … Read more
Updated: Seems $exists queries use index properly now based on these tickets $exists queries should use index & {$exists: false} will not use index Old Answer: No, there is no way to tell mongodb to use index for exists query. Indexing is completely related to data. Since $exists is only related to the keys (fields) … Read more