SQL Server is a powerful relational database management system that is widely used in the industry. It offers a wide range of features and functionalities that help in managing and manipulating data efficiently. In this article, we will explore some important concepts and ideas related to SQL Server.

Data Compression

Data compression in SQL Server 2008 comes in two flavors: row compression and page compression. Row compression changes the format of physical storage of data, minimizing the metadata associated with each record. Page compression allows common data to be shared between rows for a given page, using techniques like row compression, prefix compression, and dictionary compression.

DBCC Commands

DBCC commands in SQL Server are used for various tasks such as maintenance, gathering information, validation operations, and miscellaneous tasks. These commands act as Database Console Commands and provide a way to perform different operations on databases, indexes, filegroups, and more.

Finding Tables Without Indexes

To find tables without indexes in SQL Server, you can use the following query:

USE <database_name>;
GO

SELECT SCHEMA_NAME(schema_id) AS schema_name, name AS table_name
FROM sys.tables
WHERE OBJECTPROPERTY(OBJECT_ID, 'IsIndexed') = 0
ORDER BY schema_name, table_name;
GO

Copying Tables, Schema, and Views

There are multiple ways to copy tables, schema, and views from one SQL Server to another. You can use the “Detach Database” and “Attach Database” method, manually script all the objects using SSMS, or use the Wizard of SSMS.

Copying Data from One Table to Another

Similarly, there are multiple ways to copy data from one table to another in SQL Server. You can use the “INSERT INTO SELECT” method when the table is already created, or the “SELECT INTO” method when the table needs to be created. Both methods allow you to transfer data between tables efficiently.

Catalog Views

Catalog views in SQL Server provide a general interface to the catalog metadata. They offer an efficient way to obtain, transform, and present customized forms of information about the database. All user-available catalog metadata is exposed through catalog views.

PIVOT and UNPIVOT

PIVOT and UNPIVOT are operators in SQL Server that allow you to transform data. PIVOT turns the values of a specified column into column names, effectively rotating a table. UNPIVOT is the reverse of PIVOT and helps in converting column names into row values.

Filestream

Filestream in SQL Server allows you to store large objects in the file system and integrate them within the database. It enables the storage of unstructured data such as documents, images, audios, videos, etc. Using Transact SQL statements, you can insert, update, delete, and select the data stored in FILESTREAM enabled tables.

Dirty Read

A dirty read occurs when two operations, read and write, occur together, resulting in incorrect or unedited data. It happens when one transaction reads uncommitted data that has been changed by another transaction but not yet committed. This can lead to inconsistent or unreliable data.

SQLCMD

SQLCMD is an enhanced version of isql and osql in SQL Server. It provides more functionality and is considered a better replacement for isql and osql. SQLCMD can work in batch mode or interactive mode, offering a powerful command-line tool for executing SQL scripts and commands.

Aggregate Functions

Aggregate functions in SQL Server perform calculations on a set of values and return a single value. They are used for summarizing data and include functions like AVG, MIN, SUM, COUNT, and more. HAVING clause is often used with GROUP BY for filtering queries based on aggregate values.

Table Sample

TABLESAMPLE in SQL Server allows you to extract a random sampling of rows from a table. This can be useful when you only need a subset of data for your application instead of the entire result set. The rows retrieved are random and not in any specific order.

Row_Number() and Ranking Functions

ROW_NUMBER() is a function in SQL Server that returns the row number within the result set. It is useful for assigning a unique sequential number to each row. Ranking functions like RANK() and DENSE_RANK() are used to assign a rank to each row within a partition of a result set, based on specified criteria.

UNION vs UNION ALL

UNION and UNION ALL are used to combine the results of two or more SELECT statements in SQL Server. The main difference between them is that UNION eliminates duplicate rows, while UNION ALL includes all rows from all tables without removing duplicates. It is important to choose the appropriate one based on your specific requirements.

B-Tree

B-Tree is a data structure used by the SQL Server database server to organize index information. It consists of root nodes, branch nodes, and leaf nodes. Root nodes contain pointers to branch nodes, which in turn contain pointers to leaf nodes or other branch nodes. Leaf nodes contain index items and horizontal pointers to other leaf nodes.

These are just a few concepts and ideas related to SQL Server. The platform offers much more in terms of performance optimization, security, scalability, and advanced querying techniques. Understanding these concepts can help you become a more proficient SQL Server developer or administrator.