![]() ![]() This does not fit with my preconceived views. I do know I was surprised to find Oracle adhering to the current reference Standard document implementation (and to be fair IBM DB2 and good old Faircom c-treeACE adhere to the current Standard too), whereas most of the other RDBMS vendors were the violators. Perhaps this was one of the changes approved between the 20 Standards. Its SQL implementation strongly conforms to the ANSI-SQL:2008 standard ….”. The “ About” page of PostgreSQL even boasts “PostgreSQL prides itself in standards compliance. I’ve never had a problem – it appears a great RDBMS implementation. I often use PostgreSQL (as a back-end DBMS/I develop in C# via. MySQL is generally faster and more efficient than other relational database management systems (RDBMS), so it is often the preferred choice for applications that require high performance. The must contain a FROM clause, and as far as I can fathom, the is not optional. While SQL is a programming language used to work with data in relational databases, MySQL is an open-source database product that implements the SQL standard. I have included inline below an excerpt from ISO/IEC 9075-2:2011(E)Ĭurrently, as defined in SQL/Foundation, the FROM clause is not optional. With respect to the FROM clause, I am not sure whether the current Standard Definitions were the same as they are now when the various vendors implemented their RDBMS implementations. I decided to purchase and read the ANSI/IEC/ISO SQL standards, partly out of curiosity, and partly to formalise my understanding of the programming language. The document set is a very dry read. In Oracle, the special DUAL table can be used as, for example: Oracle has the peculiarly named DUAL table, where DUAL as a word in English indicates two parts to something (but with true Oracle clarity it is a table containing one row and a one column), that exists for the same purpose. IBM DB2 for example has the SYSIBM.SYSDUMMY1 table, where even the name gives you an indication that it’s a dummy table required for some reason. However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner. Is grammatically fine, whereas other RDBMS vendor implementations require a dummy table or sorts. Although SQL is an ANSI/ISO standard, there are different versions of the SQL language. ![]() I have believed for some time that the SQL FROM clause is optional, that is optional from the standpoint of ANSI/IEC/ISO standards, not from the standpoint of Oracle of course.įor example, in SQL Server, MySQL, PostgreSQL, and then some
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |