Tanishk

Apache CassandraBeginner

What is Cassandra

Understand what Apache Cassandra is, how its ring, replication and tunable consistency work, how to model tables in CQL, and when it is the wrong choice.

#data-modeling#scalability

IBM Db2Beginner

How to Resolve DB2 Error: DB29501E

Fix Db2 error DB29501E on Windows by setting the DB2INSTANCE environment variable to a valid instance, verify the change, and handle the related SQL1390C message.

SQL ServerBeginner

How to Convert Rows to Columns Using PIVOT in SQL Server

Turn rows into columns with the T-SQL PIVOT operator, handle NULLs and unknown column lists, and know when conditional aggregation is the better choice.

#t-sql

Apache HadoopBeginner

What are Different Data Compression Methods in Hadoop

Compare gzip, bzip2, Snappy, LZ4, Zstandard and LZO in Hadoop, understand why splittability matters, and choose a codec for MapReduce, Parquet and ORC.

#hdfs#open-source

SQL ServerBeginner

How to Delete Data in SQL Server

Delete rows safely in SQL Server: choose between DELETE, TRUNCATE and DROP, archive rows with OUTPUT, and batch large deletes to limit locking and log growth.

#sql-server-2014

SQL ServerBeginner

How to Create Credential in SQL Server

Create a SQL Server credential with T-SQL or Management Studio and use it for Agent proxies and backups to Azure Blob Storage or S3, then change or remove it safely.

PostgreSQLBeginner

Locks in PostgreSQL

Understand PostgreSQL table, row and advisory locks, see which session is blocking which, handle deadlocks and run schema changes without stalling the application.

CouchbaseBeginner

How to Install Couchbase Server

Install Couchbase Server on Linux, Windows, macOS or Docker, pick the right edition, initialise the cluster, and verify it by creating a bucket and running a query.

#data-modeling

SQL ServerBeginner

SQL Functions

Summarise data with COUNT, SUM, AVG, MIN and MAX, group and filter it with GROUP BY and HAVING, and add running totals with window aggregates.

Apache HadoopBeginner

How to Install Cloudera Virtual Machine

In this article we will learn how to install Cloudera Distributed for Hadoop (CDH) Virtual Machine .

MongoDBBeginner

What is mongod

What the mongod server process does, how it differs from mongos and mongosh, the options and config file that control it, and how to start and stop it safely.

#open-source

SQL ServerIntermediate

What is SQL Server R Services

SQL Server R Services is now Machine Learning Services. See what changed, how to enable it, how to run R or Python against a table, and when to avoid it.