![]() ![]() In the following example I show the collation problem and then repair the collation problem at the table level in MySQL. Luckily with MySQL, we can dynamically alter the collation at multiple levels: DB, TABLE, or COLUMN. The email id, in effect, require you to use case-sensitive collation if you are going to key off of them or otherwise declare them to be unique. ![]() While these email IDs are indeed unique, they can become non-unique if you are using a DB that is collating without regard to case, as was the case here (pun could possibly have been intended). The problem was that – in this particular application – Microsoft Graph API email ids where being used with a Unique constraint. This client was using Django ORM, which has no ability to use the COLLATE clause without direct SQL statements, which were not desirable. I recently ran into an issue with a client where they were using the default case-insensitive collation on a project and this was causing undesired collisions. While this may be desirable for certain applications, and can be overridden on a per-query basis with the “COLLATE” clause, it can also be very detrimental if you are not aware of it if you are using an ORM, it may not be desirable to create direct SQL statements. You might see this as: latin1_ci, utf8mb4_unicode_ci, etc, depending on the character set you have. It answers questions the DB needs to know, like: “how should upper / lower case or character accents be considered when I compare or sort something?”īy default, MySQL will use a case-insensitive collation. Its essentially a set of rules for the DB to follow when making decisions on said sort and comparison. NET 2.When using MySQL (or most any DB really), it’s a good idea to understand about collation: the implications, the defaults, and how to change it.Ĭollation determines how data is sorted and compared in the database. HtmlAgilityPack package no longer includes a.Creating a mock web service with Visual Studio.Using REPLACE on TEXT columns in Transact-SQL.Applying a license key to Windows Server2019 Evaluation Edition.Accessing ADO Execute RowsAffected in JScript.JScript.NET exception on user defined prototype method, “Function expected”. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |