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  2. Select (SQL) - Wikipedia

    en.wikipedia.org/wiki/Select_(SQL)

    Select all the rows from the beginning of the table to the last row to display ({begin_base_0 + rows}) Read the {begin_base_0 + rows} rows but send to display only when the row_number of the rows read is greater than {begin_base_0}

  3. Window function (SQL) - Wikipedia

    en.wikipedia.org/wiki/Window_function_(SQL)

    In the above table, the next query extracts for each row the values of a window with one preceding and one following row: SELECT LAG ( name , 1 ) OVER ( ORDER BY name ) "prev" , name , LEAD ( name , 1 ) OVER ( ORDER BY name ) "next" FROM people ORDER BY name

  4. Block Range Index - Wikipedia

    en.wikipedia.org/wiki/Block_Range_Index

    A particular advantage of the BRIN technique, shared with Oracle Exadata's Smart Scanning, [6] is in the use of this type of index with Big Data or data warehousing applications, where it is known that almost all of the table is irrelevant to the range of interest. BRIN allows the table to be queried in such cases by only retrieving blocks that ...

  5. Full table scan - Wikipedia

    en.wikipedia.org/wiki/Full_table_scan

    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 optimizer can't correctly estimate that using the index is faster.

  6. Database index - Wikipedia

    en.wikipedia.org/wiki/Database_index

    The data rows may be spread throughout the table regardless of the value of the indexed column or expression. The non-clustered index tree contains the index keys in sorted order, with the leaf level of the index containing the pointer to the record (page and the row number in the data page in page-organized engines; row offset in file ...

  7. PL/SQL - Wikipedia

    en.wikipedia.org/wiki/PL/SQL

    The purpose of a PL/SQL function is generally used to compute and return a single value. This returned value may be a single scalar value (such as a number, date or character string) or a single collection (such as a nested table or array). User-defined functions supplement the built-in functions provided by Oracle Corporation. [6]

  8. Hierarchical and recursive queries in SQL - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_and_recursive...

    A common table expression, or CTE, (in SQL) is a temporary named result set, derived from a simple query and defined within the execution scope of a SELECT, INSERT, UPDATE, or DELETE statement. CTEs can be thought of as alternatives to derived tables , views, and inline user-defined functions.

  9. Database trigger - Wikipedia

    en.wikipedia.org/wiki/Database_trigger

    The following is an Oracle syntax example of a row level trigger that is called AFTER an update FOR EACH ROW affected. This trigger is called on an update to a phone book database. When the trigger is called it adds an entry into a separate table named phone_book_audit.