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It also supports >REPLACE INTO syntax, [6] which first attempts an insert, and if that fails, deletes the row, if exists, and then inserts the new one. There is also an IGNORE clause for the INSERT statement, [ 7 ] which tells the server to ignore "duplicate key" errors and go on (existing rows will not be inserted or updated, but all new rows ...
This technique can either supplement or complement timestamps and versioning. It can configure an alternative if, for example, a status column is set up on a table row indicating that the row has changed (e.g., a boolean column that, when set to true, indicates that the row has changed).
In computing, data deduplication is a technique for eliminating duplicate copies of repeating data. Successful implementation of the technique can improve storage utilization, which may in turn lower capital expenditure by reducing the overall amount of storage media required to meet storage capacity needs.
For example, removing duplicates using distinct may be slow in the database; thus, it makes sense to do it outside. On the other side, if using distinct significantly (x100) decreases the number of rows to be extracted, then it makes sense to remove duplications as early as possible in the database before unloading data.
In situations where the number of unique values of a column is far less than the number of rows in the table, column-oriented storage allow significant savings in space through data compression. Columnar storage also allows fast execution of range queries (e.g., show all records where a particular column is between X and Y, or less than X.)
In December 2019, the Institute on Taxation and Economic Policy found that Salesforce was one of 91 companies who "paid an effective federal tax rate of 0% or less" in 2018, as a result of the Tax Cuts and Jobs Act of 2017. Their findings were published in a report based on the 379 Fortune 500 companies that declared a profit in 2018. [131]
The replication process can be complex and time-consuming, depending on the size and number of the distributed databases. This process can also require much time and computer resources. Duplication, on the other hand, has less complexity. It identifies one database as a master and then duplicates that database. The duplication process is ...
A number of different algorithms have been proposed to detect duplicate code. For example: Baker's algorithm. [7] Rabin–Karp string search algorithm. Using abstract syntax trees. [8] Visual clone detection. [9] Count matrix clone detection. [10] [11] Locality-sensitive hashing; Anti-unification [12]