Python – Dictionaries

What are they? A dictionary is an unordered set of key:value pairs where the value is mutable, and the key is unique and hashable.  A dictionary is defined within a set of braces {}. Objects such as dictionaries, lists, or other mutable structures may not be used as...

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Python – Sets and Tuples

  What are they? A Set is an unordered, mutable collection that will not retain duplicate values. A Tuple is an ordered, immutable, collection that can accept duplicates. How are they created? Set:  three basic ways – Using the set( ) function: s = set( )...

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Python – Lists

Lists are similar to C array types.  A list can accept any Python object, including other lists. You can create a list in several ways: a = list()    # creates an empty list (a) a = [ ]        # using brackets to create an empty list (a) a = [1,2,3,4,5]    # creates a...

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SQL Server: TempDB

Question: What is TempDB? Answer: This is a short blog post on TempDB.  TempDB is essentially a scratch database for SQL Server.  It’s also one of, if not the, busiest databases on an instance.  Learning what it does, and does not do, is important both for the DBA,...

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SQL Server 2014 Cardinality Estimator

Question: Two-part:  What is different in the new Cardinality Estimator, and how can I check to see which one I’m using? Answer: The cardinality estimator (“CE”) was changed in SQL Server 2014.  New assumptions and logic were added based upon a modern workload (OLTP...

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SQL Server: Parameter Sniffing

Question:            What is parameter sniffing, and is it a bad thing? Answer: Parameter sniffing is actually a very good thing, most of the time.  When it does go bad, it’s usually extremely bad.  I’ll define, demonstrate, and provide some ways to avoid the bad...

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