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nslookup operates in interactive or non-interactive mode. When used interactively by invoking it without arguments or when the first argument is - (minus sign) and the second argument is a hostname or Internet address of a name server, the user issues parameter configurations or requests when presented with the nslookup prompt (>).
The records returned may not be complete. For example, if there is both an A and an MX for a name, but the name server has only the A record cached, only the A record will be returned. Usually referred to as ANY (e.g., in dig, Windows nslookup, and Wireshark).
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Some DNS server packages have overcome this problem by automatically constructing the serial number from the last modification timestamp of the database file on disk. This is the case for djbdns, for example. The operating system ensures that the last modification timestamp is updated whenever an administrator edits the database file ...
SQL is a well known query language and data manipulation language for relational databases; XQuery is a query language for XML data sources; XPath is a declarative language for navigating XML documents; YQL is an SQL-like query language created by Yahoo! Search engine query languages, e.g., as used by Google [5] or Bing [6]
SQL includes operators and functions for calculating values on stored values. SQL allows the use of expressions in the select list to project data, as in the following example, which returns a list of books that cost more than 100.00 with an additional sales_tax column containing a sales tax figure calculated at 6% of the price.
The purpose of DQL commands is to get the schema relation based on the query passed to it. Although often considered part of DML, the SQL SELECT statement is strictly speaking an example of DQL. When adding FROM or WHERE data manipulators to the SELECT statement the statement is then considered part of the DML.
Active Footprinting is the process of using tools and techniques, such as performing a ping sweep or using the traceroute command, to gather information on a target. Active Footprinting can trigger a target's Intrusion Detection System (IDS) and may be logged, and thus requires a level of stealth to successfully do. [ 4 ]