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The migration of Oracle databases to Microsoft SQL Server brings many challenges. One of the most significant is associated with mapping Oracle schema to SQL Server. At the architecture level, the wrong approach will result in significant effort in the future. For example, you may even need to rewrite your app’s entire code from scratch. The problem Oracle database server includes an Oracle database and an Oracle instance. You may learn more about the architecture of the Oracle server here. […]

Mapping Oracle data types to SQL Server data types is often a problem during Oracle to Microsoft SQL Server database code conversions. A tried and trusted solution is to use an SQL Server database code conversion. Another reliable solution is to use SQL Server Migration Assistant. These solutions enable you to automate Oracle database conversions to SQL Server. However, there might be some issues you should consider while using SSMA. For example, by default, SSMA applies the maximum available size […]

A materialized view is an important property of Oracle. SQL Server recreates the same behavior as this materialized view in several ways. Unfortunately, SSMA may have issues with converting this object to SQL Server. It flags certain conditions as an error. In this blog post, we will overview the error O2SS0522. It goes about cases in which the Oracle materialized view includes FLOAT columns, subqueries, GROUP BY or WHERE clauses, MINUS, INTERSECT, UNION, etc. By default, SQL Server Migration Assistant (SSMA) converts Oracle […]

ABCloudz tech experts possess outstanding experience in migrating databases. For this purpose, we frequently use SQL Server Migration Assistant (SSMA). SSMA utilization may cause various types of errors, so we have created a blog post series which focused on typical database conversion errors. Each post in this series is dedicated to a separate problem statement and presents our recommendations on how it should be approached and fixed. Related posts Here is the list of blog posts on the most common SSMA […]

Oracle enables you to use specific interval literals for indicating a certain period of time. Unfortunately, there is no direct analog for such literals in SQL Server. As a result, when you apply SQL Server Migration Assistant (SSMA) for converting Oracle code with interval literals, you receive an error O2SS0086. The term ‘interval literals’ refers to a fixed data value, such as the constant value term. Interval literals can be specified in terms of seconds, minutes, hours, days, months, or even years. There are two […]

With Oracle table functions, you can define a set of PL/SQL statements in such a way that, when queried, should behave just as a regular query to the table. The table function enables you to manipulate individual collection elements (user-defined object types) in your SQL database code. However, this may create a database migration challenge because  SQL Server Migration Assistant (SSMA) cannot convert Oracle table functions. Instead, it generates a set of the following errors: O2SS0474: Conversion of the user-defined type […]

In Oracle, you can create a foreign key for a table using columns with various data types. Unfortunately, SQL Server Migration Assistant (SSMA) fails to convert them to SQL Server correctly since it does not support such elements. As a result, when you try to convert the Oracle code including the foreign key with the columns of different data types, you will see the following message: «Error O2SS0231: Foreign keys with different types of columns and referenced columns cannot be converted». Read this blog post to find out how […]

The pivot clause is an integral part of the Oracle database. In particular, the pivot_clause of the SELECT statement allows you to write crosstabulation queries. Here you can rotate rows into columns and aggregate data in the rotation process. As an important data warehousing element, pivot rotates a table-value expression. To be more specific, it turns the unique value from one expression column into multiple output columns. Besides, pivot performs aggregations where they are needed on any of the remaining column values […]

In Oracle, database links are important features that enable you to access objects on another database. SQL Server has a direct alternative to this function. It provides a linked server or an OPENQUERY feature that allows you to emulate the database links’ functionality. Unfortunately, SQL Server Migration Assistant (SSMA) fails to convert these links automatically. When you try converting a database link query that refers to remote objects, you get the following error: “O2SS0563: Conversion of database link … is not […]

Preventing clients from overspending is one of our top priorities. Hence, we pay close attention to the cost of Oracle to SQL server migration in order to provide the most economical solutions while keeping the highest level of quality. Over years, we have served many clients and helped them to keep costs under control. For example, we successfully completed an Oracle to SQL Server migration proof of concept project ordered by a governmental organization from South America. While working on the project, […]

Oracle databases have many specific functions and features. For example, it stores a period of time with specific interval expressions. This may cause issues during the database migration from Oracle to SQL Server. When you use SQL Server Migration Assistant (SSMA) for converting Oracle with interval expressions, you will observe the O2SS0006 error message. This may happen because that SSMA does not support type mapping for such expressions. There are intervals of 2 kinds in the source Oracle code: INTERVAL DAY TO SECOND and INTERVAL YEAR TO […]

Proprietary database features often create significant obstacles for developers. To demonstrate as an example, we will take a look at one of Oracle’s most valuable proprietary features – Oracle Call Interface (OCI). It ensures efficient communication between the database and the application code. Surely, you may use other options for connecting to Oracle. However, once you have committed to OCI, switching to another interface becomes a real headache. Read our new blog post to understand how you can overcome challenges […]

Defining a naming convention for the conversion of packaged procedures and functions is a very important step during migration of Oracle database to Microsoft SQL Server. Experienced architects usually point out that this step is as significant as setting schema and data type mapping. Naming convention should be defined at the beginning of the migration project. Let’s discuss in detail why this step is so important and what type of issues you may experience if not defining naming convention properly. […]

Database migration to Microsoft SQL Server 2019 brings your software data management to a new level. It makes your application more secure, scalable, and customizable. Unfortunately, 44% of digitized businesses state that the lack of technical understanding is one of the main obstacles to successful database modernization. How can they overcome this problem? The solution requires a comprehensive approach and a full understanding of the best practices. We strongly advise to take advantage of the latest version of SQL Server 2019. In […]

One of our clients contacted ABCloudz to request help with their SQL Server app’s performance issues. They upgraded from SQL Server 2008 R2 to SQL Server 2019 and began experiencing problems shortly after. We analyzed their database system and discovered a complex issue with updating SQL Server statistics. These stats are used by the Query Optimizer to create an execution plan for each query. The problem was that the time to update statistics was taking much longer than the planned […]