In terms of programming, a database management system is a software for creating and managing databases. DBMS allows us to create, protect, read, update and delete data in a database. It works as an interface between databases and us or application programs. A few popular examples are MySQL...
“Unable to enlist in the transaction” with Oracle linked server from MS SQL Server [<Name of Missing Index, sysname,>] in non clustered index [Execute SQL Task] Error: The value type (__ComObject) can only be converted to variables of type Object. [ODBC Driver Manager] Data sourc...
Quite often there’s a need to create a read-only replica of a SQL Server database. This might be required, for example, for the purpose of separating analytical and operative tasks. The first cause high load on databases and in order to reduce it, the replica of the primary database i...
i want to clone other database with the same ( which i deleted) when i am trying to create a database it is saying that the name already exists. when i go there to the physical path and tried to rename the file it is saying like the file is in use. is there a way to rename ...
For MySQL, we’ll use the predefined indexprogram_department_id_fkeyin the tableProgram. For SQL Server we’ll use a new index. Therefore, let’s create a nonclustered column store indexcalledcsindx_simplein the tableProgram: CREATENONCLUSTERED COLUMNSTORE INDEX csindx_simpleONProgram (departme...
MySQL has a limited set (relative to Oracle) of possible keys: INDEX (aka KEY) -- just an index; stored separately from the data. UNIQUE -- INDEX, plus UNIQUEness constraint. PRIMARY KEY -- Always UNIQUE, always (in InnoDB) 'clustered' with the data, implicitly NOT NULL. ...
Let us assume we have a non-clustered index on thenamecolumn and half of the table has valuesriand few rows havepalin thenamecolumn. For the first query, SQL Server will use the table scan because half of the table has the same values. But for the second query, it is better to use...
You can compare MySQL indexes with the index in a book which lets you easily find the correct page that contains the subject you’re looking for. If there weren’t any indexes, you’d have to go through the whole book searching for pages that contain the subject. As you can imagine, ...
David has over 40 years of industry experience in software development and information technology and a bachelor of computer science In this lesson, we'll take a look at SQL and SQL script, how to create SQL script, and how to run SQL script. At the end, you should have a good understa...
MySQL EXPLAIN join types The EXTRA column in MySQL EXPLAIN Hands-on example of how to use MySQL EXPLAIN Confirm that the database is created and seeded Run the initial query Optimization approach 1: Create two individual indexes Optimization approach 2: Use a multi-column index Conclusion Want ...