modifying databases in vwd

... database. Next, the following example sets the InsertCommand property of mySqlDataAdapter to myInsertCommand: mySqlDataAdapter.InsertCommand = myInsertCommand; Setting the UpdateCommand Property ... one wins" concurrency. To use optimistic concurrency, you have to do the following in your UPDATE or DELETE statement's WHERE clause: 1. Include all the columns used in the original ... a DataRow using the BeginEdit() method. Setting the DeleteCommand Property of a DataAdapter The following example creates a SqlCommand object named myDeleteCommand that contains a DELETE...

Ngày tải lên: 24/12/2013, 01:17

... by the method call. In this example, one is returned since one row was added. Modifying a DataRow in a DataTable To modify a DataRow in a DataTable, you use the following steps: 1. Set the ... dataTableName is a string containing the name of the DataTable to update. The int returned by the Update() method is the number of rows successfully updated in the database. Going back to the previous ... need to set this to find the DataRow in the next step. 2. Use the Find() method to locate the DataRow that you want to modify in your DataTable. You locate the DataRow using the value of its...

Ngày tải lên: 24/12/2013, 01:17

Ngày tải lên: 12/02/2014, 12:20

Ngày tải lên: 17/02/2014, 11:20

Ngày tải lên: 23/03/2014, 20:20

Ngày tải lên: 31/05/2014, 00:13

... data in which none of that is necessary, a world in which all pipeline datasets are contained in the single table that is their destination or their point of origin. In this world, maintaining ... systems used in education, finance, health care, insurance, manufacturing, retailing and transportation—all industries in which the authors have had consulting experience. In using these methods, ... along inflow pipelines, and posted transactions as data destined for some kind of logfile, and as moving towards that destination along outflow pipelines. So if we can bring pending transactions into...

Ngày tải lên: 24/12/2013, 02:16

... management losing faith in data warehouse projects. As these large projects fell increasingly behind schedule and rose increasingly over budget— something large projects tend to do—the pressure increased to ... first restoring them from off-line storage media. After that, the next step was to realize that there was value, not just in having a par- ticular set of backup data remain on-line, but also in having ... columns. In addition, developers were also beginning to create on-line transaction tables by bringing collections of transactions back from off-line storage media, transactions that originally...

Ngày tải lên: 24/12/2013, 02:16

... point in time forward to the point in time we are interested in. But the defining feature of reconstructable methods is not the movement of data from off-line to on-line storage. The defining ... waiting for the data, and the decisions delayed until the data becomes available. In an increasingly fast-paced business world, the opportunity cost of delays in accessing data is increasingly ... any point in time between the starting balance and the current bal- ance by going back to the starting balance and applying trans- actions, in chronological sequence, up to the desired point. We...

Ngày tải lên: 24/12/2013, 02:16

... by also inter- nalizing them within their target tables. In this book, we will show how the use of these internalized managed objects reduces the costs of maintaining databases by replacing external ... designing and maintaining data models that must explicitly define temporal data structures and integrity constraints on them. It also relieves developers of the burden of designing, writing and maintaining ... lacking a standard for the PERIOD datatype, we will continue the practice of defining periods of time in terms of their begin and end points in time. Chapter 3 THE ORIGINS OF ASSERTED VERSIONING:...

Ngày tải lên: 24/12/2013, 02:16

... just one kind of internalized pipeline dataset, and the internalization of pipeline datasets can eliminate a large part of the IT maintenance budget by eliminating the need to manage pipeline datasets ... perhaps joining data that the production queries did not have to join, perhaps assembling intermediate results and then combining those intermediate results in various complicated ways. In short, ... is the SQL statement that inserted or most recently altered the data in that table. In each table, primary key columns are indicated by under- lining their column headings. In each table, the italicized...

Ngày tải lên: 24/12/2013, 02:16

... objects monitored by instruments, such as atomic nuclei or automobile engines. The objects that businesses are interested in generally fall in the mid-range in terms of being static or dynamic. Both ... a business user says that a policy should be deleted, she is (or should be) making a business statement. She is saying that as of a given point in time, the policy is no longer in effect. In a ... semantic constraints on bi-temporal data as that data is maintained, Asserted Versioning makes queries against its tables nearly as easy to write as queries against conventional tables. In the final section...

Ngày tải lên: 24/12/2013, 02:16

... truth. Temporal Integrity Constraints The three integrity constraints in relational theory are entity integrity, referential integrity and domain integrity. Entity integ- rity insures that the ... present an in- line notation for single asserted Managing Time in Relational Databases. Doi: 10.1016/B978-0-12-375041-9.00006-6 Copyright # 2010 Elsevier Inc. All rights of reproduction in any form ... business data in a row is no longer in effect. In other words, the date which is one clock tick past the last date on which the business data in a row is in effect. Asr-beg. Assertion begin date....

Ngày tải lên: 24/12/2013, 02:16

... within shared assertion time, even a single effective-time clock tick included in another version of that object already in the table. Most physical transactions against bi-temporal tables are inserts. ... are known. Perhaps in another insurance company, all policies stop being in effect at the end of each calendar year. In that case, instead of an effective end date of 12/31/9999 in rows 1 and 3, ... with, the possibility of misinterpretation, on the maintenance side of things, is minimized. But what about the query side of things? What about looking at the data in an asserted version table?...

Ngày tải lên: 24/12/2013, 02:16

... SCENARIO 153 PART 3 DESIGNING, MAINTAINING AND QUERYING ASSERTED VERSION DATABASES Chapter Contents 8. Designing and Generating Asserted Versioning Databases 167 9. An Introduction to Temporal ... referential integrity on those tables. If ERwin is used as the data modeling tool, then a set of ERwin 162 Part 3 DESIGNING, MAINTAINING AND QUERYING ASSERTED VERSION DATABASES Note that, like all temporal ... of “filling in the gap” between those two episodes, merging them into a single episode. In this chapter, however, we assume that our temporal insert creates a new episode. An episode begin date...

Ngày tải lên: 21/01/2014, 08:20

... Table. Chapter 8 DESIGNING AND GENERATING ASSERTED VERSIONING DATABASES 173 8 DESIGNING AND GENERATING ASSERTED VERSIONING DATABASES CONTENTS Translating a Non-Temporal Logical Data Model into a Temporal Physical ... that each business key points to one and only one object by defining a unique index on it. Nor can we simply extend the scope of the index by defin- ing a unique index on the business key plus ... that correspond to rows in a conventi onal table of persistent objects. 164 Part 3 DESIGNING, MAINTAINING AND QUERYING ASSERTED VERSION DATABASES In this chapter, we focus on index design, although...

Ngày tải lên: 21/01/2014, 08:20

... significantly reduces the work involved in maintaining temporal data, and will eliminate the errors that would otherwise inevitably happen as temporal data is maintained. Using a framework like the ... taxonomy in terms of its topology. On a line representing a timeline, we can place a line segment representing an episode. We can also remove a line segment from that line. Given a line segment, ... archives at Information_Management.com (formerly DM Review), with links listed in the bibliography. 188 Chapter 8 DESIGNING AND GENERATING ASSERTED VERSIONING DATABASES Typically, a single standard...

Ngày tải lên: 21/01/2014, 08:20

... will continue on, and will update the database. In doing so, it will begin by preserving the original state of the version or versions about to be changed, doing this by withdrawing them into past ... shown in Figure 10.3. Episode C, as we have labeled it, is a single-version episode. Of course all episodes, when initially created, are single-version episodes. Using the in- line notation introdu ... or a referential integrity constraint, it will reject that transaction. In response, the AVF will stop processing the temporal transaction, undo Managing Time in Relational Databases. Doi: 10.1016/B978-0-12-375041-9.00010-8 Copyright # 2010...

Ngày tải lên: 21/01/2014, 08:20

... temporal deletes as well. In addition, instead of requiring the user to write trans- actions in a proprietar y format required by an Application Programming Interface (API) we were developing, the AVF now ... episode. Splitting an Episode {Splitting} an episode is a little more interesting than either {shortening an episode backwards} or {shortening an episode for- wards}. The reason is that, from the point ... resulting episodes, {splitting} is {shortening an episode backwards}, while from the point of view of the later of the two resulting episodes, it is {shortening an episode forwards}. From the point...

Ngày tải lên: 21/01/2014, 08:20

Ngày tải lên: 21/01/2014, 08:20