thị trường với các sản phẩm cơ sở dữ liệu thương mại đầu tiên quan hệ: quan hệ phần mềm của Oracle và các quan hệ công nghệ của Ingres. IBM phát hành SQL / DS vào năm 1982, với ngôn ngữ truy vấn hiện nay có tên là SQL (Hệ thống Query Language). Khi IBM phát hành RDBMS thế hệ tiếp theo của nó, được gọi là DB2, | CHAPTER 4 Introduction to SQL marketplace with the first commercial relational database products Relational Software s Oracle and Relational Technology s INGRES. IBM released SQL DS in 1982 with the query language now named SQL System Query Language . When IBM released its next generation RDBMS called DB2 the SQL acronym remained but the language name had morphed into Structured Query Language. The name change was likely the result of marketing spin structured programming was the mantra of the day and although SQL has nothing to do with programming structured or otherwise anything with the word structured in its title got more attention in the marketplace. SQL standards committees were formed by ANSI American National Standards Institute in 1986 and ISO International Organization for Standardization in 1987. Two years later the first standard specification known as SQL-89 was published. The standard was expanded three years later into SQL-92 which weighed in at roughly 600 pages. The third generation was called SQL-99 or SQL3. Most RDBMS products are built to the SQL-92 now called SQL2 standard. SQL3 includes many of the object features required for SQL to operate on an object-relational database as well as language extensions to make SQL computationally complete adding looping branching and case constructs . Only a few vendors have implemented significant components of the SQL3 standard Oracle being one of them. Nearly every vendor has added extensions to SQL partly because they wanted to differentiate their products and partly because market demands pressed them into implementing features before there were standards for them. One case in point is support for the DATE and TIMESTAMP data types. Dates are highly important in business data processing but the developers of the original RDBMS products were computer scientists and academics not business computing specialists so such a need was unanticipated. As a result the early SQL dialects did not have any special .
