sequences

问题 I have start date as "2017-11-14 10:11:01 CET" and end date as "2017-11-15 01:15:59 CET". I want to create timestamps of 500 milliseconds each, between these start and end timestamps. E.g. I need a dataframe containing the following output timestamp 2017-11-14 10:11:01.000 2017-11-14 10:11:01.500 2017-11-14 10:11:02.000 2017-11-14 10:11:02.500 . . . 2017-11-15 01:15:59.000 Somehow, I managed to get the start and end date in milliseconds using the following code: start.date <- strptime("2017

问题 Does anyone have a good way of implementing something like a sequence in SQL server? Sometimes you just don't want to use a GUID, besides the fact that they are ugly as heck. Maybe the sequence you want isn't numeric? Besides, inserting a row and then asking the DB what the number is just seems so hackish. 回答1: Sql Server 2012 has introduced SEQUENCE objects, which allow you to generate sequential numeric values not associated with any table. Creating them are easy: CREATE SEQUENCE Schema

问题 I have a class hierarchy: abstract DomainObject { ... @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator="SEQ") @SequenceGenerator(name="SEQ",sequenceName="SEQ_DB_NAME") @Column(name = "id", updatable = false, nullable = false) private Long id; ... } BaseClass extends DomainObject { ... // Fill in blank here where this class's @Id will use a unique sequence generator // bonus points for any sort of automatic assignment of generator names that might //prevent me from having to

问题 Given a starting number, imagine an infinite sequence of its successive halves. 1, 0.5, 0.25, 0.125, ... (Ignore any numerical instabilities inherent in double .) Can this be done in a single expression without writing any custom extension methods or generator methods? 回答1: I don't know of a single-expression way but I found this clever generator code here: http://csharpindepth.com/articles/Chapter11/StreamingAndIterators.aspx public static IEnumerable<TSource> Generate<TSource>(TSource start

问题 Reading the Wikipedia article on UTF-8, I've been wondering about the term overlong . This term is used various times but the article doesn't provide a definition or reference for its meaning. I would like to know if someone can explain the term and its purpose. 回答1: It's an encoding of a code point which takes more code units than it needs to. For example, U+0020 is represented in UTF-8 by the single byte 0x20 . If you decode the two bytes 0xc0 0xa0 in the normal fashion, you'll still end up

问题 Find the n'th term of DJ(i). Given DJ(i) is the number of times i is present in DJ(i) The array DJ(i) is as shown: i 1 2 3 4 5 6 7 8 9 10 ..... DJ(i) 1 2 2 3 3 4 4 4 5 5 ..... I want the nth term of the series DJ(i). I have to carry out some further calculations with the term. 回答1: Look up the value in this table or compute yourself the table in the programming language of your choice (left as an easy exercise). Also check this SO answer and OEIS. 来源： https://stackoverflow.com/questions

问题 I am using oracle sequence for inserting log id into tableA as follows, String SQL_PREP_INSERT = "INSERT INTO tableA (LOG_ID,USER_ID,EXEC_TIME) VALUES" + " (logid_seq.nextval, ?, ?)"; Then getting the recently inserted value, String SQL_PREP_SEL = "SELECT max(LOG_ID) FROM tableA "; stmt = con.prepareStatement(SQL_PREP_SEL); stmt.execute(); ResultSet rs = stmt.getResultSet(); if (rs.next()) { logid = rs.getInt(1); } And inserting it into tableB, String SQL_PREP_INSERT_DETAIL = "INSERT INTO

问题 I am using oracle sequence for inserting log id into tableA as follows, String SQL_PREP_INSERT = "INSERT INTO tableA (LOG_ID,USER_ID,EXEC_TIME) VALUES" + " (logid_seq.nextval, ?, ?)"; Then getting the recently inserted value, String SQL_PREP_SEL = "SELECT max(LOG_ID) FROM tableA "; stmt = con.prepareStatement(SQL_PREP_SEL); stmt.execute(); ResultSet rs = stmt.getResultSet(); if (rs.next()) { logid = rs.getInt(1); } And inserting it into tableB, String SQL_PREP_INSERT_DETAIL = "INSERT INTO

问题 I am using oracle sequence for inserting log id into tableA as follows, String SQL_PREP_INSERT = "INSERT INTO tableA (LOG_ID,USER_ID,EXEC_TIME) VALUES" + " (logid_seq.nextval, ?, ?)"; Then getting the recently inserted value, String SQL_PREP_SEL = "SELECT max(LOG_ID) FROM tableA "; stmt = con.prepareStatement(SQL_PREP_SEL); stmt.execute(); ResultSet rs = stmt.getResultSet(); if (rs.next()) { logid = rs.getInt(1); } And inserting it into tableB, String SQL_PREP_INSERT_DETAIL = "INSERT INTO

问题 /* A Naive recursive implementation of LIS problem */ #include<stdio.h> #include<stdlib.h> /* To make use of recursive calls, this function must return two things: 1) Length of LIS ending with element arr[n-1]. We use max_ending_here for this purpose 2) Overall maximum as the LIS may end with an element before arr[n-1] max_ref is used this purpose. The value of LIS of full array of size n is stored in *max_ref which is our final result */ int _lis( int arr[], int n, int *max_ref) { /* Base