SQL Azure Introduction

SQL Azure is part of Microsoft Azure Service Platform which provides data storage/manipulations capabilities to the platform. SQL Azure uses a special version of SQL Server as backend. This provides two editions of database namely   Business Edition and Web Edition. Maximum database size in Business edition can be of 150 GB and 5 GB for Web edition. Being a cloud based service; it provides high availability by storing multiple copies of databases and in addition that it provides elastic scale and rapid provisioning. You pay as you go and increase/decrease the capacity of the server on demand as it is Infrastructure As A Service.

Being a special version of SQL server there are some differences as what is available and what is not available. Some of these differences are:

  • FileStream data is not available. All other native data types are available excluding the CLR type.
  • 3 and 4 part name are not available i.e. you can’t refer any object by server and database. It supports only two part name (Schema.Object) and this is because databases are fully Contained in SQL Azure.
  • USE statement is not available. I am missing that a lot. You can’t execute USE myDatabase
  • Backup and restore are not available to users.
  • Create and Drop database are available but filegroup management and database file placement are not available.
  • Total number of databases can be 150 including master.
  • System tables and SQL Server Configuration options are not available.
  • SQL Server Replication and database mirroring are not available.  Data Sync is available to sync data between on-premises to cloud and cloud to cloud.
  • Full text index not available
  • CDC and Data Compression are not available
  • Table partitioning (partitioning Function and scheme)
  • All tables MUST have a Clustered Index. Although you can create one but you can’t insert data into that.
  • Extended Stored Procedures not available
  • SQL Server Agent (Jobs and schedule) are not available.
  • Only SQL Serve Authentications are available. No more windows integrated security.
  • The default transaction isolation level in SQL Azure is READ_COMMITTED_SNAPSHOT while it is READ_COMMITTED in SQL Server.
  • You can you SSMS to work with Azure databases but Wizards will not be available and you have to do everything and anything by using T-SQL. SQLCMD can be used too.
  • Global temporary ( ##temp) tables are not supported.
  • DDL triggers are not supported.

Now I hope you have some idea about what is SQL Azure and what are its limitations. Microsoft provides 3 months limited Evolution subscription for SQL Azure.  In my next blog I will share information on creating your 1st database in SQL Azure.

 

Regards

Rakesh Mishra

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