#Navicat premium sql dump a view how to#
#Navicat premium sql dump a view update#

Moreover, views and tables share the same namespace within the database, so you can't give your view the same name as any existing table of view. You can choose whatever name you wish for your view, so long as you follow the same naming rules as for tables. MySQL chooses the MERGE algorithm first, due to its greater efficiency, but falls back to the TEMPTABLE algorithm if MERGE cannot be employed. The UNDEFINED algorithm lets MySQL make a choice of using MERGE or TEMPTABLE algorithm.

UNDEFINED is the default algorithm when you create a view without specifying an explicit algorithm.

Because MySQL has to create a temporary table to store the result set and moves the data from the base tables to the temporary table, the TEMPTABLE algorithm is less efficient than the MERGE algorithm.

The TEMPTABLE algorithm first creates a temporary table based on the SELECT statement that defines the view, and then it executes the input query against this temporary table.

If the MERGE algorithm cannot be applied, MySQL automatically changes the algorithm to UNDEFINED. The MERGE algorithm cannot be applied to SELECT statements that contain aggregate functions such as MIN, MAX, SUM, COUNT, AVG or DISTINCT, GROUP BY, HAVING, LIMIT, UNION, and UNION ALL.

MySQL then executes the combined query to return the merged result set. The MERGE algorithm combines the input query with the SELECT statement, which defines the view, into a single query.MySQL provides three algorithms: MERGE, TEMPTABLE, and UNDEFINED: The ALGORITHM attribute tells MySQL which mechanism to use when creating the view. Now, let's examine the syntax in more detail. In MySQL, you use the CREATE VIEW statement to create a new view.

#Navicat premium sql dump a view how to#

In today's blog, we'll learn what a view is and how to create one for MySQL 8 using Navicat Premium as our client.

#Navicat premium sql dump a view update#

Most database management systems, including MySQL, even allow you to update data in the underlying tables through the view, but with some caveats. Much like a database table, a view also consists of rows and columns that you can query against. A database view is a virtual or logical table which is comprised of a SELECT query.