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Log shipping is the process of automating the backup of transaction log files on a primary (production) database server, and then restoring them onto a standby server. This technique is supported by Microsoft SQL Server , [ 1 ] 4D Server , [ 2 ] MySQL , [ 3 ] and PostgreSQL .
In SQL the UNION clause combines the results of two SQL queries into a single table of all matching rows. The two queries must result in the same number of columns and compatible data types in order to unite. Any duplicate records are automatically removed unless UNION ALL is used.
Prev LSN: A link to their last log record. This implies database logs are constructed in linked list form. Transaction ID number: A reference to the database transaction generating the log record. Type: Describes the type of database log record. Information about the actual changes that triggered the log record to be written.
A server log is a log file (or several files) automatically created and maintained by a server consisting of a list of activities it performed. A typical example is a web server log which maintains a history of page requests. The W3C maintains a standard format (the Common Log Format) for web server log files, but other proprietary formats ...
The relational algebra uses set union, set difference, and Cartesian product from set theory, and adds additional constraints to these operators to create new ones.. For set union and set difference, the two relations involved must be union-compatible—that is, the two relations must have the same set of attributes.
Application- or user-specific database objects in relational databases are usually created with data definition language (DDL) commands, which in SQL for example can be CREATE, ALTER and DROP. [4] [5] Rows or tuples from the database can represent objects in the sense of object-oriented programming, but are not considered database objects. [6]
Common Log File System (CLFS) is a general-purpose logging subsystem that is accessible to both kernel-mode as well as user-mode applications for building high-performance transaction logs. It was introduced with Windows Server 2003 R2 and included in later Windows operating systems.
In relational databases, the log trigger or history trigger is a mechanism for automatic recording of information about changes inserting or/and updating or/and deleting rows in a database table. It is a particular technique for change data capturing , and in data warehousing for dealing with slowly changing dimensions .