1) Explain what are identifiers and rules for defining identifiers in mysql?
Identifiers are names of columns,tables,indexes,views,Stored Procedures,Triggers etc.
Identifiers can start with any character including digit, but it should not consists of completely digits.
Identifiers can consists of letters,digits,dollar,underscore.
An Identifiers names can have a maximum length of 64 characters.
An alias name can have a maximum characters of up to 255 characters. Continue reading
241) Explain importance of Object class in java?
java.lang.Object class represents java object. Object class is the super class for all predefined and user defined classes in java.Each and every class in java extends Object class. Methods defined in Object class are important because they appear in every instance of class. Continue reading
We use split() method in String class for splitting the given String.
String class split method returns array of string objects. We use for loop
to iterate in reverse order to print the strings in reverse order.
16) Which command is used to display structure of table?
We can use describe command to display structure of table. We use this command to display columns names,datatypes etc and shows whether column is nullable or not nullable. Continue reading
6) Explain DML statements in SQL?
||Used to retrieve data from database. Continue reading
1) Explain primary key?
Primary key : Primary key is used to uniquely identify a row in table.
Each table can have only one primary key.
We cannot insert nulls for primary key values.
We cannot insert duplicate values in primary key column.
Example : For example if we take Students table students table contains student id, which is used to uniquely identify a record in table. Continue reading