1. Copy One database to other on same hostmysqldump -uroot -p source_database_name | mysql -uroot dest_database_name2. Copy database from one host to other host.mysqldump -uroot -p source_database | ssh host2 "mysql -uroot dest_database"
Month: February 2010
Dynamic creation of variables in ruby
1. To create local variables in ruby dynamically.Use eval method in rubyree-1.8.7-2010.01 > eval("local=4") => 4 ree-1.8.7-2010.01 > p local4ree-1.8.7-2010.01 > eval("local_#{1}=4") => 4 ree-1.8.7-2010.01 > puts local_142. To create & get instance variables dynamically in ruby.instance_varaiable_set & instance_varaiable_get methods are provided and no need to do it using eval.ree-1.8.7-2010.01 > (0..3).each do |i|ree-1.8.7-2010.01 > instance_variable_set("@instance_#{i}", i*i+1)ree-1.8.7-2010.01 ?> … Continue reading Dynamic creation of variables in ruby
Eval method in ruby
Eval method in ruby executes string/expression passed as parameter.Example:ree-1.8.7-2010.01 > eval("5+3") => 8 ree-1.8.7-2010.01 > eval("a=5") => 5 ree-1.8.7-2010.01 > eval("b||=a") => 5 Its part of ruby meta-programming and not recommended approach unless there is no any alternative to do.
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