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SQL refers to Structured Query Language, a kind of language used to access, update and manipulate database. In SQL, ROLLBACK is a command that causes all data changes since the last START TRANSACTION or BEGIN to be discarded by the relational database management systems (RDBMS), so that the state of the data is "rolled back" to the way it was before those changes were made.
A savepoint is a way of implementing subtransactions (also known as nested transactions) within a relational database management system by indicating a point within a transaction that can be "rolled back to" without affecting any work done in the transaction before the savepoint was created. Multiple savepoints can exist within a single ...
The transaction, commit and rollback concepts are key to the ACID property of databases. [1] A COMMIT statement in SQL ends a transaction within a relational database management system (RDBMS) and makes all changes visible to other users. The general format is to issue a BEGIN WORK (or BEGIN TRANSACTION, depending on the database vendor ...
A database transaction symbolizes a unit of work, performed within a database management system (or similar system) against a database, that is treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes:
Previous Page: sort the data in the reverse order, select only the first {rows} rows, where the {unique_key} is less than {first_val} (the value of the {unique_key} of the first row in the current page), and sort the result in the correct order; Read and send to display all the rows read from the database
A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. [1] A well known example is the Structured Query Language (SQL).
MS SQL Server supports trigger for DML and DDL statement plus special trigger "logon". The scope of DDL triggers can be a database (CREATE TRIGGER name ON DATABASE ...) or the entire SQL Server instance (CREATE TRIGGER name ON ALL SERVER). When you use the entire instance, you can capture all events executed on commands that have server-level scop
Columns: The different transactions in the schedule. Rows: The time order of operations (a.k.a., actions). Operations (a.k.a., actions): R(X): The corresponding transaction "reads" object X (i.e., it retrieves the data stored at X). This is done so that it can modify the data (e.g., X=X+4) during a "write" operation rather than merely overwrite it.