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Project Stuff.


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Project Stuff Reminder: Phase II is due next week (Thursday, April 10) Read the project description and what each phase is asking for! After some discussion with the TA, I have simplified the project a bit and clarified some other parts of it, as follows:
Transcripts
Slide 1

Venture Stuff Reminder: Phase II is expected one week from now (Thursday, April 10) Read the undertaking portrayal and what every stage is requesting! After some talk with the TA, I have rearranged the task a bit and elucidated some different parts of it, as takes after: THINGS YOU NO LONGER NEED TO WORRY ABOUT: the auto dealership no more rents autos, they just offer new autos the auto dealership no more manages contracts

Slide 2

Project Stuff (2) GENERAL ASSUMPTIONS: you can't expect away a prerequisite acknowledge checks and collaborations for the DMV and bank (for getting a credit) are past the extent of this database framework. the dealership as of now has a pile of impermanent labels, they don't have to contact the DMV for them. They should have the capacity to print out a report of what impermanent label numbers were issued, and when they were issued, and protect that each transitory label issued is not the same as each other one given out in the most recent 30 days.

Slide 3

Project Stuff (3) GENERAL ASSUMPTIONS proceeded with: the dealership may purchase autos from more than one maker, in this way they may be offering more than one make of auto. For instance, Chevy dealerships additionally administration and offer Geos; Dodge dealerships likewise benefit Plymouths, et cetera. The quantity of diverse auto makers sold will be little (1, 2, 3 … not more than around 5 or something like that greatest) the dealership just offers new autos, however regardless it manages utilized autos when they are exchanged. These autos are promptly transported to an utilized auto merchant which is strategically placed adjacent so the new auto dealership does not need to stress over staying informed regarding this utilized auto on the parcel.

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Project Stuff (4) GENERAL ASSUMPTIONS proceeded with: Negotiations with banks for auto credits are not took care of by the dealership. Either a man purchasing an auto will as of now come in with a credit from a bank, or some standard auto advance philosophy happens that does not require any connection with the database. From the dealership's viewpoint, any auto deal (paying little respect to credits) is similar to they are purchasing the auto in full with money. the administration office will deal with autos that were not purchased from the dealership, the length of it is a sort they find themselves able to benefit. For the venture, you can accept any auto brought for administration will be a sort of auto they can take a shot at.

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Project Stuff (5) DATA ASSUMPTIONS (and clues): the sum total of what vehicles have VIN's (vehicle recognizable proof numbers) which are 17 alpha-numeric characters so they will must be information by a client. client distinguishing proof numbers are NOT government disability numbers. connections to other information are typically done by utilizing key(s), so be cautious for excess information when a connection by means of key(s) would be easier. Information excess will nibble you later on.

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Project Stuff (6) DATA ASSUMPTIONS and insights (kept): wrangling is not some piece of the database, but rather another auto will have two costs connected with it: the makers recommended retail value (MSRP) and the value the auto was really sold for. The auto's expense (how much the dealership paid the maker for it) might be altogether not quite the same as both the above costs. Autos being repaired, yet not purchased from here won't require a cost for the auto

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Project Stuff (7) TASK ASSUMPTIONS: when requesting a vehicle from a producer, you won't get quick criticism. It is kind of like requesting from a paper index, you send in what you need (and your cash) and in the end, you get what you requested or a note saying it is out of stock. The real exchange of cash will be managed by the outer charging framework, yet you must produce an exchange's record when you make the request, and redesign it when the auto comes in. all together for a client to by a custom auto, either repaired at the dealership or straight from the maker or both, they need to purchase the auto first.

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Project Stuff (8) TASK ASSUMPTIONS: recollect, there are two approaches to redo an auto: modify an auto on the parcel or request a custom auto from the maker. It is conceivable that customization will be done both courses for one auto.

Slide 9

What Now? Most as of late we took a shot at Chapter 11: Storage and File Structure. Presently we begin Chapter 12: Indexing and Hashing 12.1 Basic Concepts 12.2 Ordered Indices 12.3 B+-tree Index Files 12.4 B-tree Index Files 12.5 Static Hashing 12.6 Dynamic Hashing 12.7 Comparison of Ordered Indexing and Hashing 12.8 Index Definition in SQL 12.9 Multiple-Key Access

Slide 10

Motivation Query reaction velocity is a noteworthy issue in database plan Some questions just need to get to a little extent of the records in a database “Find all records at the Perryridge bank branch” “Find the equalization of record number A-101” “Find all records claimed by Zephraim Cochrane” Checking each and every record for the inquiries above is extremely wasteful and moderate. To permit quick access for those sorts of questions, we make extra structures that we take up with documents: files (list records).

Slide 11

Basic Concepts Indexing techniques are utilized to accelerate access to craved information e.g. Creator card index in a library Search key - a quality or set of credits used to turn upward records in a document. This utilization of the word key varies from that utilized before as a part of class. A file document comprises of records (list passages) of the structure: (search-key, pointer) where the pointer is a connection to an area in the first document Index documents are normally much littler than the first record Two fundamental sorts of file: requested lists : pursuit keys are put away in sorted request hash lists : inquiry keys are circulated consistently crosswise over “buckets” utilizing a “hash function”

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Index Evaluation Metrics We will take a gander at various systems for both requested indexing and hashing. Nobody system is best in all circumstances - each has its points of interest and disservices. The components that can be utilized to assess distinctive records are: Access sorts upheld proficiently. Discovering records with a predefined characteristic quality Finding records with property estimations inside of a predetermined scope of qualities Access (recovery) time. Discovering a solitary fancied tuple in the document. Insertion time Deletion time Update time Space overhead for the file

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Index Evaluation Metrics (2) Speed issues are Access time Insertion time Deletion time Update time Access is the operation that happens the most oftentimes, in light of the fact that it is additionally utilized for supplement, erase, redesign For addition, erase, and overhaul operations we must consider not just the ideal opportunity for the operation itself (embeddings another record into the document) additionally whenever needed to upgrade the list structure to reflect changes. We will regularly need to have more than one file for a document e.g., card lists for creator, subject, and title in a library

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Ordered Indices A requested list stores the seek's estimations keys in sorted request records in the first document might themselves be put away in some sorted request (or not) the first record may have a few files, on diverse pursuit keys when there are various files, an essential list is a list whose hunt scratch likewise decides the sort request of the first document. Essential records are additionally called bunching files optional files are files whose hunt key determines a request unique in relation to the successive request of the document. Additionally called non-grouping files a list successive record is a requested consecutive document with an essential file.

Slide 15

Dense and Sparse Indices A thick file is the place a list record shows up for each hunt key worth in the document A meager list contains file records for just some inquiry key qualities relevant when records are consecutively requested on the pursuit key to find a record with inquiry key worth K we must: discover list record with biggest inquiry key quality <=K pursuit document successively beginning at the area indicated stop (come up short) when we hit a record with inquiry key quality >K less space and less upkeep overhead for addition, erase for the most part slower than thick list for finding records

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Example of a Dense Index

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Example of a Sparse Index

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Problems with Index-Sequential Files Retrieve: seek until the key quality or a bigger key worth is discovered individual key access BAD filter the record all together of the key GOOD Insert is hard - all higher key records must be moved to put the new record Delete may leave gaps Update is proportional to a joined erase and supplement redesigning a pursuit key field may bring about the consolidated drawbacks of a supplement and an erase by moving the record’s area in the sorted record differential documents are regularly used to hold the late overhauls until the database can be revamped disconnected from the net.:

Slide 19

Multi-level Index If the essential file does not fit in memory, access gets to be extravagant (plate peruses expense) To lessen the quantity of circle gets to list records, we treat the essential file continued circle as a successive document and develop an inadequate list on it If the external list is still too expansive, we can make another level of list to file it, thus on Indices at all levels must be upgraded on insertion or cancellation from the record

Slide 20

Index Update: Deletion When erasures happen in the essential record, the list will here and there need to change If the erased record was the main record in the document with its specific pursuit key esteem, the hunt key is erased from the list additionally Single-level file erasure: thick lists - cancellation of hunt key is like record erasure scanty lists - if a passage for the inquiry key exists in the file, it is supplanted by the following pursuit key worth in the first record (taken in hunt key request) Multi-level list erasure is a basic augmentation of the above

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Index Update: Insertion As with cancellations, when insertions happ