Search results
Results from the WOW.Com Content Network
A surrogate key is frequently a sequential number (e.g. a Sybase or SQL Server "identity column", a PostgreSQL or Informix serial, an Oracle or SQL Server SEQUENCE or a column defined with AUTO_INCREMENT in MySQL). Some databases provide UUID/GUID as a possible data type for surrogate keys (e.g. PostgreSQL UUID [3] or SQL Server ...
However, SELECT COUNT(*) can't count the number of null columns. The query is unselective The number of return rows is too large and takes nearly 100% in the whole table. These rows are unselective. The table statistics does not update The number of rows in the table is higher than before, but table statistics haven't been updated yet. The ...
A schedule is serial if the executed transactions are non-interleaved (i.e., a serial schedule is one in which no transaction starts until a running transaction has ended). Schedule D is an example of a serial schedule:
A sequence number is a consecutive number in a sequence of numbers, usually of real integers (natural numbers).Sequence numbers have many practical applications. They can be used, among other things, as part of serial numbers on manufactured parts, in case management, [1] or in databases as a surrogate key for registering and identifying unique entries in a table [2] [3] (in which case it is ...
Dimension tables often use primary keys that are also surrogate keys. Surrogate keys are often auto-generated (e.g. a Sybase or SQL Server "identity column", a PostgreSQL or Informix serial, an Oracle SEQUENCE or a column defined with AUTO_INCREMENT in MySQL). The use of surrogate dimension keys brings several advantages, including: Performance.
A product key, also known as a software key, serial key or activation key, is a specific software-based key for a computer program. It certifies that the copy of the program is original. It certifies that the copy of the program is original.
The term serial number is sometimes used for codes which do not identify a single instance of something. For example, the International Standard Serial Number or ISSN used on magazines, journals and other periodicals, an equivalent to the International Standard Book Number (ISBN) applied to books, is assigned to each periodical.
serial numbers, assigned incrementally or sequentially, by a central authority or accepted reference. random numbers , selected from a number space much larger than the maximum (or expected) number of objects to be identified.