c# barcode generator open source AN OVERVIEW AND ANALYSIS OF PROPOSALS BASED ON THE TSQL2 APPROACH in Font

Making QR in Font AN OVERVIEW AND ANALYSIS OF PROPOSALS BASED ON THE TSQL2 APPROACH

CHAPTER 28 AN OVERVIEW AND ANALYSIS OF PROPOSALS BASED ON THE TSQL2 APPROACH
QR-Code Creator In None
Using Barcode maker for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Paint QR Code In None
Using Barcode printer for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Explanation: The specification AS VALIDTIME ... (in line 3 of the CREATE TABLE for suppliers and line 4 of the CREATE TABLE for shipments) indicates that tables S and SP are tables with validtime support; i.e., they have hidden valid-time columns. They are not packed on those columns (perhaps because such packing could lead to a violation of temporal upward compatibility, if the AS VALIDTIME ... specification appeared in an ALTER TABLE rather than CREATE TABLE, as here and the table in question currently contained any duplicate rows). The specification PERIOD (DATE) following AS VALIDTIME gives the data type for the hidden valid-time columns; PERIOD is a type constructor (it is the TSQL2 counterpart of our INTERVAL type generator), and DATE is the corresponding point type.10 Note: TSQL2 could not use the keyword INTERVAL here, because the SQL standard already uses that keyword for something else. More to the point, observe that of course any TSQL2 table, regardless of whether or not it has any kind of temporal support, can have any number of regular columns of some period type. As noted earlier, TSQL2 regards such columns as containing what it calls user-defined time [10]. The VALIDTIME prefixes on the primary key and foreign key specifications specify that the corresponding constraints are valid-time sequenced constraints. Moreover:
EAN / UCC - 14 Creator In None
Using Barcode creator for Font Control to generate, create GS1 128 image in Font applications.
www.OnBarcode.com
European Article Number 13 Encoder In None
Using Barcode generator for Font Control to generate, create EAN 13 image in Font applications.
www.OnBarcode.com
A VALIDTIME PRIMARY KEY constraint is analogous, somewhat, to a WHEN / THEN constraint as defined in reference [6] (except that we do not believe in the idea of being forced to single out some specific candidate key and make it primary, and as a matter of fact neither does SQL). It is not clear whether TSQL2 allows a VALIDTIME PRIMARY KEY constraint to coexist with a regular PRIMARY KEY constraint, though it is clear that the existence of a VALIDTIME one makes a regular one more or less redundant. A VALIDTIME FOREIGN KEY constraint is analogous, again somewhat, to a foreign U_key constraint as defined in reference [6]. Note that the referenced table S, in our example must have valid-time support in order for the VALIDTIME FOREIGN KEY constraint to be valid.
Make GTIN - 12 In None
Using Barcode creator for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
Create Barcode In None
Using Barcode creation for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Absence of the VALIDTIME prefix on a primary or foreign key specification, in the presence of AS VALIDTIME, means the corresponding constraint is a current one; that is, it applies only to those rows whose valid-time component is considered to contain the current time (speaking rather loosely). Suppose now, in contrast to the foregoing, that the nontemporal tables S and SP have already been defined, thus:
Generate Barcode In None
Using Barcode maker for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Painting 4-State Customer Barcode In None
Using Barcode maker for Font Control to generate, create 4-State Customer Barcode image in Font applications.
www.OnBarcode.com
10. Note that TSQL2 follows its keywnrd PERIOD with the name of the point type in parentheses, whereas we follow our keyword INTERVAL with the name of the point type attached by means of an underscore instead. A related observation is that the TSQL2 analog of what we would express as, e.g., INTERVAL_DATE ([di:dj]) is just PERIOD ([di:dj]); in other words, TSQL2 assumes the type of the interval or period, rather can be inferred from the type of the begin and end points di and dj. We do not agree with this latter position, for reasons explained in detail in reference [6].
Print QR Code JIS X 0510 In Visual Studio .NET
Using Barcode encoder for VS .NET Control to generate, create QR Code 2d barcode image in VS .NET applications.
www.OnBarcode.com
QR-Code Generator In None
Using Barcode creation for Online Control to generate, create QR Code 2d barcode image in Online applications.
www.OnBarcode.com
CHAPTER 28 AN OVERVIEW AND ANALYSIS OF PROPOSALS BASED ON THE TSQL2 APPROACH
Draw UCC-128 In None
Using Barcode maker for Online Control to generate, create UCC - 12 image in Online applications.
www.OnBarcode.com
EAN / UCC - 13 Decoder In Visual Basic .NET
Using Barcode scanner for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
CREATE TABLE S ( S# S#, PRIMARY KEY ( S# ) ) ; CREATE TABLE SP ( S# S#, P# P#, PRIMARY KEY ( S#, P# ), FOREIGN KEY ( S# ) REFERENCES S ) ; Suppose further that we now wish to add valid-time support to these tables (remember the goal of temporal upward compatibility). Then the following more or less self-explanatory ALTER TABLE statements will suffice (again, note the text in boldface): ALTER TABLE S ADD VALIDTIME PERIOD ( DATE ) ; ALTER TABLE S ADD VALIDTIME PRIMARY KEY ( S# ) ; ALTER TABLE SP ADD VALIDTIME PERIOD ( DATE ) ; ALTER TABLE SP ADD VALIDTIME PRIMARY KEY ( S#, P# ) ; ALTER TABLE SP ADD VALIDTIME FOREIGN KEY ( S#) REFERENCES S ; In rows that already exist when the valid-time support is added, the new (hidden) column is set to contain a period of the form [b:e], where b is the time of execution of the ALTER TABLE and e is the end of time. 11 Whether it is necessary to drop the primary and foreign keys that were defined for the tables before the valid-time support was added is unclear.
Creating UPC Symbol In Java
Using Barcode generator for Java Control to generate, create UPC-A Supplement 2 image in Java applications.
www.OnBarcode.com
Making Barcode In Visual C#.NET
Using Barcode generation for .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
Print USS-128 In Java
Using Barcode generator for BIRT Control to generate, create EAN 128 image in BIRT reports applications.
www.OnBarcode.com
Barcode Decoder In Visual Basic .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Linear 1D Barcode Creator In .NET Framework
Using Barcode drawer for ASP.NET Control to generate, create 1D Barcode image in ASP.NET applications.
www.OnBarcode.com
Draw EAN13 In Java
Using Barcode generator for Android Control to generate, create EAN-13 image in Android applications.
www.OnBarcode.com
Generate Code 128 Code Set A In None
Using Barcode encoder for Word Control to generate, create Code 128A image in Word applications.
www.OnBarcode.com
Barcode Creator In VS .NET
Using Barcode creator for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.