IT Trainer Questions

I am History.

Yes, history refers to all the past, but we can create history in the presentand it cannot be polluted in the future.

Android uses Dalvik Virtual Machine (DVM) which requires a special bytecode. We need to convert Java class files into Dalvik Executable files using an Android tool called "dx". In normal circumstances, developers will not be using this tool directly and build tools will care for the generation of DVM compatible files.

The three major amendments that were passed shortly after the Civil War are the reconstruction amendments that were the 13th, 14th, and 15th amendments.

The 13th Amendment abolished slavery,

The 14th granted African American citizenship and equal protection before the law, (and)

The 15th Amendment attempted to secure the right to vote for newly freed slaves. 

The difference between Union and Union all is that Union all will not eliminate duplicate rows, instead it just pulls all rows from all tables fitting your query specifics and combines them into a table. A UNION statement effectively does a SELECT DISTINCT on the results set.

Foreign keys are the columns of a table that points to the primary key of another table. They act as a cross-reference between tables.

In detail : A Foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table or the same table. In simpler words, the foreign key is defined in a second table, but it refers to the primary key or a unique key in the first table.

In the mesh topology, each computer is connected to the other with a separate physical link in a network. It is most reliable topology as the network does not get down in case one of the nodes is failed.

In a database table, the category of information is called Field.