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The name Selenium comes from a joke made by Huggins in an email, mocking a competitor named Mercury, saying that you can cure mercury poisoning by taking selenium supplements. The others that received the email took the name and ran with it.
XPath (XML Path Language) is an expression language designed to support the query or transformation of XML documents. It was defined by the World Wide Web Consortium (W3C) in 1999, [1] and can be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document.
A table (called the referencing table) can refer to a column (or a group of columns) in another table (the referenced table) by using a foreign key. The referenced column(s) in the referenced table must be under a unique constraint, such as a primary key. Also, self-references are possible (not fully implemented in MS SQL Server though [5]).
A common table expression, or CTE, (in SQL) is a temporary named result set, derived from a simple query and defined within the execution scope of a SELECT, INSERT, UPDATE, or DELETE statement. CTEs can be thought of as alternatives to derived tables ( subquery ), views , and inline user-defined functions.
Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.
The SQL language is subdivided into several language elements, including: Keywords are words that are defined in the SQL language. They are either reserved (e.g. SELECT, COUNT and YEAR), or non-reserved (e.g. ASC, DOMAIN and KEY). List of SQL reserved words. Identifiers are names on database objects, like tables, columns and schemas. An ...
Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form:
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 ...