Anand Sunderraman. Anand Sunderraman Anand Sunderraman 7, 29 29 gold badges 82 82 silver badges bronze badges. Not an answer per-se, but this is how it works at a high level in Oracle. Can you provide the specific product that you intend? If your target product is SQL Server, then this article is a good place to start. Add a comment. Active Oldest Votes. First you have a syntax check, followed by the generation of an expression tree - at this stage you can also test whether elements exist and "line up" i.
This is the first step - any error here any you just tell the submitter to get real. Then you have Set based logic. So you get a query analyzer in depending on product bad to good - oracle long time has crappy ones, DB2 the most sensitive ones even measuring disc speed to decide how best to approach this result.
This is a really complicated beast - it may try dozens or hundreds of approaches to find one he believes to be fastest cost based, basically some statistics. Then that gets executed. Noctis TomTom TomTom TomTom thanks, as you say I need not bother about the table formats but I really want to know it out of curiosity.
If I were to design a Db maybe I would store my tables in csvs and do say strinfg processing to retrieve data, but I just wanted to know how others did it?? SQL Server the only I know the details uses a file in 8kb pages with it's own management structure defining what the page contains. There are index pages, data pages etc. Query plans explain exactly into what a SQL query is translated. With the progress in database technology SQL-based applications have become increasingly affordable for the regular user.
The SQL Standard has gone through a lot of changes during the years, which have added a great deal of new functionality to the standard, such as support for XML, triggers, regular expression matching, recursive queries, standardized sequences and much more. In a lot of cases, the database behavior for file storage or indexes is not well defined and it's up to the vendors of the various SQL implementations to decide how the database will behave.
This is the reason why, even though all SQL implementations have the same base, they are rarely compatible. The SQL language is based on several elements. For the convenience of SQL developers all necessary language commands in the corresponding database management systems are usually executed through a specific SQL command-line interface CLI.
Expressions - the expressions can produce scalar values or tables, which consist of columns and rows of data. Predicates - they specify conditions, which are used to limit the effects of the statements and the queries, or to change the program flow.
This popularity is due to its flexibility in supporting distributed databases. Distribution of databases across several system networks, concurrently, is possible due to this flexibility.
Considered by many the database query standard, SQL powers some of the most potent database applications on today's Internet. Those seeking SQL Server training for beginners can find it available through a lot of portals online and in the form of lab-based classes.
Today, SQL based applications are working both on corporate and individual servers. The SQL standard has changed over the years. These changes have added to the functionality of SQL-based programs and include:.
Most database solutions do not incorporate the entire SQL standard, because it is massive. It's up to database designers to make the database behave as they want. This choice is the reason most SQL databases are not cross-compatible.
Several different elements make up SQL. A specific Command Line Interface CLI executes language commands for developers' convenience in most database management systems.
SQL statements help database administrators to generate queries from a client program to the database. Users can execute a wide range of fast data manipulation using these statements.
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