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Since the Leszynski naming convention is a special form of Hungarian notation the same general advantages also apply to the Leszynski convention.. The use of distinctive prefixes makes your database self-documenting; when you see frmSales in VBA code, you will know that it references a form, and when you see curSales you will know that it is a Currency variable.
Microsoft Query is a visual method of creating database queries using examples based on a text string, the name of a document or a list of documents. The QBE system converts the user input into a formal database query using Structured Query Language (SQL) on the backend, allowing the user to perform powerful searches without having to explicitly compose them in SQL, and without even needing to ...
However, some databases reject the statement if no data is given, such as Microsoft SQL Server, and in this case the DEFAULT keyword can be used. INSERT INTO phone_book VALUES ( DEFAULT ) Sometimes databases also support alternative syntax for this; for example, MySQL allows omitting the DEFAULT keyword, and T-SQL can use DEFAULT VALUES instead ...
The EXCEPT ALL operator does not remove duplicates, but if a row appears X times in the first query and Y times in the second, it will appear (,) times in the result set. Notably, the Oracle platform provides a MINUS operator which is functionally equivalent to the SQL standard EXCEPT DISTINCT operator.
The latest version of MDAC (2.8) consists of several interacting components, all of which are Windows specific except for ODBC (which is available on several platforms). ). MDAC architecture may be viewed as three layers: a programming interface layer, consisting of ADO and ADO.NET, a database access layer developed by database vendors such as Oracle and Microsoft (OLE DB, .NET managed ...
Surrogate keys tend to be a compact data type, such as a four-byte integer. This allows the database to query the single key column faster than it could multiple columns (which are often text - which is even further slower). Furthermore, a non-redundant distribution of keys causes the resulting b-tree index to be completely balanced.
"Don't repeat yourself" (DRY), also known as "duplication is evil", is a principle of software development aimed at reducing repetition of information which is likely to change, replacing it with abstractions that are less likely to change, or using data normalization which avoids redundancy in the first place.
OLE 1.0, released in 1990, was an evolution of the original Dynamic Data Exchange (DDE) concept that Microsoft developed for earlier versions of Windows.While DDE was limited to transferring limited amounts of data between two running applications, OLE was capable of maintaining active links between two documents or even embedding one type of document within another.