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30

To quote Joe Celko (not only can you find this reference all over the web and in his Wikipedia entry, but you will even see it on T-shirts at some conferences): Rows are not records. A lot of people point him out as a pedantic jerk who just likes to humble and verbally abuse newbies, and I will admit that is how he comes across. But I have also met him ...


25

Microsoft has in several places in their organization provided that the official name for tabular data storage per table-entry (to coin a taxonomic definition that serves my own purpose) is called a "ROW". I submit as evidence ROW_NUMBER, ROWCOUNT, ROWVERSION and the DataTable.Rows property, where a DataTable is a C# representation of a TSQL "table" object. ...


20

Both composite key and compound key describe a candidate key with more than one attribute. According to the Relational Database Dictionary (C.J.Date) they mean the same thing. In ER modelling the term "compound key" also has a more specific meaning. It means a key whose constituent attributes are references to keys in other entities - i.e. a compound key ...


17

I've just searched through the document "Information technology — Database languages — SQL Part 2: Foundation (SQL/Foundation)", which defines the ANSI standard for SQL as implemented by all major RDBMSes. The word row is used primarily throughout the document several hundred times, as expected. The word record was only used to describe a record that is ...


13

I'm still not sure why http://en.wikipedia.org/wiki/Compound_key was not consulted. It very clearly states (and is correct): In database design, a compound key is a key that consists of 2 or more attributes that uniquely identify an entity occurrence. Each attribute that makes up the compound key is a simple key in its own right. This is often ...


13

Horizontal Scaling Horizontal Scaling is essentially building out instead of up. You don't go and buy a bigger beefier server and move all of your load onto it, instead you buy 1+ additional servers and distribute your load across them. Horizontal scaling is used when you have the ability to run multiple instances on servers simultaneously. Typically it is ...


10

Because relational databases are rarely used in isolation, in order to avoid confusion between other parts of systems, I always refer to tables and rows and columns. In a client applications, we typically have other constructs, including datareaders, datasets, datarows, datatables, etc - for instance "field" is often used for on-screen data entry and Pascal ...


7

In Oracle terminology, it is an Index Organized Table, commonly referred to as an IOT. An index-organized table has a storage organization that is a variant of a primary B-tree. Unlike an ordinary (heap-organized) table whose data is stored as an unordered collection (heap), data for an index-organized table is stored in a B-tree index structure in a ...


6

A junction table is a weak entity, but a weak entity may be a junction table. A junction table is not the same as a weak entity. A junction table is a type of weak entity. Tables used to resolve repeating groups are also weak entities. These are only junction tables if the repeating group contains a repeated foreign key relationship.


6

Does "Heterogeneous" just refer to querying two different database engines in this context? Basically, yes. A "heterogeneous" query is executed on a "heterogeneous linked server". All queries to this linked server will be heterogeneous. And "heterogenous" is a subset of distributed queries Distributed data stored in multiple instances of SQL ...


5

The language keeps evolving. A few decades ago the literate people used "indices" instead of simpler "indexes". As we switched to "indexes", we eliminated an unnecessary complication and made the language more useful. The need to memorize a plural for "index" was pure overhead - it did not in any way help us communicate. Make no mistake, there used to be ...


5

A "candidate key" is any column or collection of columns that CAN uniquely identify a record in a table. A "primary key" is a candidate key that is defined as the primary key for the table. Internally, a primary key is simply a unique index, clustered or non-clustered, that is typically used in foreign key relationships. There is more to it than this, as ...


5

A securable is anything that can have permissions granted, denied, or revoked on in SQL Server. It's basically "something you can secure". Think about it like this: Your car is a securable. You would have to have been given keys (permissions) to access your car (securable). A securable is anything that can be accessible or inaccessible. Take a look at ...


5

In any case, when one thing hasMany of another how/where does it show up in application and database logic? The only way I can think to answer this question is with another example of hasMany that may or may not answer your question. err, except I should have called the table "comment" but I think the point stands. I don't know that this really ...


5

User terms surrogate key and natural key for primary key as a variant. Surrogate Key: Surrogate keys are keys that have no “business” meaning and are solely used to identify a record in the table. Such keys are either database generated (example: Identity in SQL Server, Sequence in Oracle, Sequence/Identity in DB2 UDB etc.) or system ...


4

A compound key would also define what you're describing. I've heard it called other things as well, like composite key. But note that the composite key is not the same as a compound key. Just trying to alert you to two vocabulary words.


3

Essentially the source table is the place where the data is coming from and the target table is the place where the data is going to or the table that an action is taking place on. They do not have to be in different schema's or have a different structure to each other and in fact they could actually be the same table.


2

A composite key consists of more than one attribute to uniquely identify an entity occurrence. This differs from a compound key in that one or more of the attributes, which make up the key, are not simple keys in their own right. For example, you have a database holding your CD collection. One of the entities is called tracks, which holds details of the ...


2

In English it is "composite keys". For instance, take a look at MSDN website (any search containing "sql composite key" will do). http://www.google.com/search?q=sql+composite+key+site:msdn.microsoft.com Assuming that the question regards Relational Databases, I searched for a "neutral" definition in Wikipedia: A composite key is a key made up of two or ...


2

Although your question is already answered very well. I would like to add my points too. May be you find it helpful upto some extend. Also my answer is not specific to SQL Server These words are used interchangeably. 1 2 3 4 -------------------------------------------------------------------- Row = Record = Tuple ...


1

It's generally called paging. Different vendors have implemented it in different ways. SQL Server was late in adopting the standard (OFFSET/FETCH in SQL Server 2012); prior to that you had to use wacky tricks with CTEs and ROW_NUMBER(), and I forget what we did in SQL Server 2000. #temp tables? MySQL chose to one-finger salute the standard and use LIMIT. ...


1

Would it still be considered a "Weak" Entity if the junction table declares its columns with FK constraints and has a composite primary key of those columns? (In other words every row is required to be a valid reference from one table to the other and all such mappings are unique within the junction table).



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