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To delete record with the lowest id, you can use the following syntax:delete from yourTableName order by yourColumnName limit 1;Let us first create a table:mysql> create table DemoTable ( Id int, Name varchar(20) ); Query OK, 0 rows affected (0.75 sec)Following is the query to insert records in the table using insert command:mysql> insert into DemoTable values(10, 'Larry'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(100, 'Mike'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(30, 'Sam'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(90, 'Chris'); Query ... Read More
Details about HashMap and WeakHashMap that help to differentiate them are given as follows −HashMap in JavaA HashMap has key-value pairs i.e. keys that are associated with the values and the keys are in arbitrary order. A HashMap object that is specified as a key is not eligible for garbage collection. This means that the HashMap has dominance over the garbage collector.A program that demonstrates this is given as follows −Example Live Demoimport java.util.*; class A { public String toString() { return "A "; } public void finalize() { System.out.println("Finalize method"); ... Read More
A SecureRandom object can be obtained using the getInstance() method in class java.security.SecureRandom. This SecureRandom object is useful in implementing the Random Number Generator (RNG) algorithm that is specified.The getInstance() method requires a single parameter i.e. the Random Number Generator (RNG) algorithm and it returns the SecureRandom object.A program that demonstrates this is given as follows −Example Live Demoimport java.security.*; import java.util.*; public class Demo { public static void main(String[] argv) { try { SecureRandom sRandom = SecureRandom.getInstance("SHA1PRNG"); String s = "Apple"; byte[] arrB = ... Read More
Following is the example which uses getHeaderNames() method of HttpServletRequest to read the HTTP header information. This method returns an Enumeration that contains the header information associated with the current HTTP request.Once we have an Enumeration, we can loop down the Enumeration in the standard manner. We will use the hasMoreElements() method to determine when to stop and the nextElement() method to get the name of each parameter name. HTTP Header Request Example HTTP Header Request Example ... Read More
The tag used as a nested action for the tag and the tag to supply a value for a value placeholder. If a null value is provided, the value is set to SQL NULL for the placeholder.AttributeThe tag has the following attributes −AttributeDescriptionRequiredDefaultValueValue of the parameter to setNoBodyExampleTo start with the basic concept, let us create an Employees table in the TEST database and create few records in that table as follows −Step 1Open a Command Prompt and change to the installation directory as follows −C:\> C:\>cd Program Files\MySQL\bin C:\Program Files\MySQL\bin>Step 2Login to the database as ... Read More
The averagingLong() method of the Collectors class returns a Collector that produces the arithmetic mean of a long-valued function applied to the input elements.The syntax is as followsstatic Collector averagingLong(ToLongFunction
The syntax is as follows to update a column with an int based on orderset @yourVariableName=0; update yourTableName set yourColumnName=(@yourVariableName:=@yourVariableName+1) order by yourColumnName ASC;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table updateColumnDemo -> ( -> Id int, -> OrderCountryName varchar(100), -> OrderAmount int -> ); Query OK, 0 rows affected (1.76 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into updateColumnDemo(Id, OrderCountryName) values(10, 'US'); Query OK, 1 row affected (0.46 sec) mysql> insert into updateColumnDemo(Id, OrderCountryName) ... Read More
You can use DROP INDEX for this. The syntax is as follows −alter table yourTablename drop index yourUniqueName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table removeUniquenessConstraint -> ( -> Id int, -> Name varchar(100), -> Age int, -> isGreaterThan18 bool, -> UNIQUE(Id, isGreaterThan18) -> ); Query OK, 0 rows affected (0.69 sec)Now check the details of table with the help of SHOW CREATE command. The query is as follows −mysql> show create table removeUniquenessConstraint;Here is the output −+----------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | ... Read More
Open your firebase page (https://console.firebase.google.com/) as shown below –Now select your project. In our case we have tutorialspoint project. It will direct to console page of project as shown below –Now scroll down right side menu to grow as shown below –In Grow tab select Cloud messaging as shown below –Now click on new notification button. It will redirect to compose message button as shown below –Now write your message as shown below –Now click on next to go target tab. Now select project as shown below –Now click on next button to go schedule as shown below –Now click ... Read More
Here, we will use OCTET_LENGTH to check the length of a record since we want the records with length more than 1. Let us first create a table −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserName varchar(20), UserGender varchar(20) ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName, UserGender) values('John', 'M'); Query OK, 1 row affected (0.82 sec) mysql> insert into DemoTable(UserName, UserGender) values('Carol', 'Male'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable(UserName, UserGender) values('Mia', 'Female'); Query OK, ... Read More