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I. Introduction of row migration and row link in actual work we often encounter some problems with low Oracle database performance. Of course, there are many reasons that cause low Oracle database performance, we can use some correct design and
Oracle Lock table row-level lock table-level lock ----row is locked exclusively ----Other users cannot modify this line until a row's lock is released----use the commit or the rollback command to release the lock ----Oracle by using INSERT, UPDATE,
A lock is a mechanism by which a computer coordinates multiple processes or a purely thread concurrently accessing a resource. in a database, data is a resource that is shared by many users in addition to the contention of traditional computing
18. Create and use a view tableView tableView table conceptsCreate a viewModify and delete a tableEnhanced viewing table functionality in SQL Server 2000SummaryIn Chapter 17th, we learned about indexes. indexes are a secondary database structure
Reference article:SQL Server Cursor Utilization: View all table size information for a database (Sizes of all Tables in a databases)Share a SQL Server script (calculate the amount of data for each table in the database and the space occupied by each
Reprint Please specify: theviper http://www.cnblogs.com/TheViperPartially translated from How to select the First/least/max row per group in SQLSome common SQL problems have similar workarounds, such as finding the most recent logs for each program,
For more information about bugs fixed in SQL Server 2000 Service Pack 4, click the following article number to view the article in the Microsoft Knowledge Base:314128 FIX: When an RPC call is performed, Access with conflicting values includes an
MySQL row-level lock, table-level lock, page-level lock details page-level: engine BDB.
Table-level: engine MyISAM, which is interpreted as locking the entire table and reading at the same time.
Row-level: engine INNODB, locking a single row of
Overview compared to other databases, MySQL's locking mechanism is relatively simple, and its most notable feature is that different storage engines support different locking mechanisms. MySQL can be broadly categorized into the following 3 types of
MySQL row-level locks, table-level locks, page-level locks, mysql details
Page Level: Engine BDB. Table-level: Engine MyISAM, which is interpreted as locking the entire table. It can be read at the same time but cannot be written at the row level.
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