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Questions tagged [sequence]

A sequence is an ordered list of objects (or events). Like a set, it contains members (also called elements or terms), and the number of terms (possibly infinite) is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence. In a relational database, a sequence is an object that is used to generate unique numbers for a primary key.

A sequence is an ordered list of objects (or events). Like a set, it contains members (also called elements or terms), and the number of terms (possibly infinite) is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence.

Sometimes, sequence is used as a generic name for both list, array and set for convenience.

In a , a sequence is an object that is used to generate unique numbers for a .

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Python: check if an object is a sequence

In python is there an easy way to tell if something is not a sequence? I tried to just do: if x is not sequence but python did not like that
nicotine
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How to slice a list from an element n to the end in python?

I'm having some trouble figuring out how to slice python lists, it is illustrated as follows: >>> test = range(10) >>> test [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> test[3:-1] [3, 4, 5, 6, 7, 8] >>> test[3:0] [] >>> test[3:1] [] >>> test [0, 1, 2, 3, 4,…
FurtiveFelon
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How can I get all sequences in an Oracle database?

Is there any command that I can run so that I can get all the sequences? I am using Oracle 11g. I am using Toad for Oracle to connect to it. I can visually see the sequences in Toad, but I like to know the command line for it.
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Why does Python allow out-of-range slice indexes for sequences?

So I just came across what seems to me like a strange Python feature and wanted some clarification about it. The following array manipulation somewhat makes sense: p = [1,2,3] p[3:] = [4] p = [1,2,3,4] I imagine it is actually just appending…
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How does the JPA @SequenceGenerator annotation work

I am learning JPA and have confusion in the @SequenceGenerator annotation. To my understanding, it automatically assigns a value to the numeric identity fields/properties of an entity. Q1. Does this sequence generator make use of the database's…
Amit
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Scala: Remove duplicates in list of objects

I've got a list of objects List[Object] which are all instantiated from the same class. This class has a field which must be unique Object.property. What is the cleanest way to iterate the list of objects and remove all objects(but the first) with…
parsa
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Best way to reset an Oracle sequence to the next value in an existing column?

For some reason, people in the past have inserted data without using sequence.NEXTVAL. So when I go to use sequence.NEXTVAL in order to populate a table, I get a PK violation, since that number is already in use in the table. How can I update the…
Cade Roux
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How to append or prepend on a Scala mutable.Seq

There's something I don't understand about Scala's collection.mutable.Seq. It describes the interface for all mutable sequences, yet I don't see methods to append or prepend elements without creating a new sequence. Am I missing something obvious…
Jean-Philippe Pellet
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can't multiply sequence by non-int of type 'float'

Why do I get an error of "can't multiply sequence by non-int of type 'float'"? from the following code: def nestEgVariable(salary, save, growthRates): SavingsRecord = [] fund = 0 depositPerYear = salary * save * 0.01 for i in…
user425727
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Sequential Guid Generator

Is there any way to get the functionality of the Sql Server 2005+ Sequential Guid generator without inserting records to read it back on round trip or invoking a native win dll call? I saw someone answer with a way of using rpcrt4.dll but I'm not…
Chris Marisic
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When to use forEach(_:) instead of for in?

As documented in both Array and Dictionary forEach(_:) Instance methods: Calls the given closure on each element in the sequence in the same order as a for-in loop. Nevertheless, adapted from Sequence Overview: A sequence is a list of values…
Ahmad F
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Get current value from a SQL Server SEQUENCE

I want to get the current value from my sequence - the same value that is shown in the sequence properties window SQL Server Management Studio My sequence is created with this statement: CREATE SEQUENCE [OrderNumberSequence] as int START…
Henrik Stenbæk
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Postgresql - Using subqueries with alter sequence expressions

Is it possible to use subqueries within alter expressions in PostgreSQL? I want to alter a sequence value based on a primary key column value. I tried using the following expression, but it wouldn't execute. alter sequence public.sequenceX restart…
Danmaxis
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Oracle: sequence MySequence.currval is not yet defined in this session

What does this mean, and how can I get around it? SELECT MySequence.CURRVAL FROM DUAL; Result: ORA-08002: sequence MySequence.CURRVAL is not yet defined in this session
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Compute the minimal number of swaps to order a sequence

I'm working on sorting an integer sequence with no identical numbers (without loss of generality, let's assume the sequence is a permutation of 1,2,...,n) into its natural increasing order (i.e. 1,2,...,n). I was thinking about directly swapping the…
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