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You can add a primary key constraint to a column of a table using the ALTER TABLE command.SyntaxALTER TABLE table_name ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (column1, column2...);Assume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as shown below:+--------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ProductName | varchar(255) | YES | | NULL | | | CustomerName | varchar(255) | ... Read More
This is a C++ program to find SSSP (Single Source Shortest Path) in DAG (Directed Acyclic Graphs) using Dijkstra Algorithm to find out from the first node in graph to every other node with the shortest path length showed beside each pair of vertices.AlgorithmBegin Take the elements of the graph as input. function shortestpath(): Initialize the variables a[i] = 1 d[i] = 0 s[i].from = 0 Initialize a loop for i = 0 to 3 do if b[0][i] == 0 continue else ... Read More
The syntax for multiple inserts for a single column in MySQL is as follows −INSERT INTO yourTableName(yourColumnName) values(‘yourValue1'), (‘yourValue2'), (‘yourValue3'), (‘yourValue4'), .........N;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table InsertMultipleDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserName varchar(10), -> UserRole varchar(20) -> , -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (3.14 sec)Now you can insert some records in the ... Read More
The setAt2() method is used to set the Septet value in JavaTuples and a copy with a new value at the specified index i.e. index 2 here.Let us first see what we need to work with JavaTuples. To work with Septet class in JavaTuples, you need to import the following package −import org.javatuples.Septet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Septet Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Septet; ... Read More
To get data from MySQL database, you need to use executeQuery() method from java. First create a table in the MySQL database. Here, we will create the following table in the ‘sample’ databasemysql> create table javaGetDataDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > FirstName varchar(10), - > LastName varchar(10) - > ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in the table using insert command.The query is as followsmysql> insert into javaGetDataDemo(FirstName, LastName) values('John', 'Smith'); Query OK, 1 row affected (0.19 sec) mysql> insert into javaGetDataDemo(FirstName, LastName) values('Carol', ... Read More
In this program we need to find the Edge Connectivity of a Graph. An Edge Connectivity of a Graph of a graph means it is a bridge, removing it graph will be disconnected. Number of connected components increases with the removing of bridge in a disconnected undirected graph.Functions and pseudocode:Begin Function connections() is a recursive function to find out the connections: A) Mark the current node un visited. B) Initialize time and low value C) Go through all vertices adjacent to this D) Check if the subtree rooted with x has a connection to one ... Read More
This example demonstrate How to use hash set in AndroidStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken the name and record number as Edit text, when user click on save button it will store the data into arraylist. Click on the refresh button to get the changes of ... Read More
To select dates in 30-day range, you can use arithmetic operation - with interval.The syntax is as follows −select *from yourTableName where yourDateColumnName > NOW() - INTERVAL 30 DAY and yourDateColumnName < NOW() + INTERVAL 30 DAY;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectDatesDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ArrivalDate datetime -> ); Query OK, 0 rows affected (0.77 sec)Now you can insert some records in the table using insert command. The query is as ... Read More
This is C++ Program to Generate All Subsets of a Given Set in the Lexico Graphic Order. This algorithm prints all the possible combination of each length from the given set of array in increasing order. The time complexity of this algorithm is O(n*(2^n)).AlgorithmBegin For each length ‘i’ GenAllSubset() function is called: 1) In GenAllSubset(), if currLen is more than the reqLen then return. 2) Otherwise, if currLen is equal to reqLen then there will be a new sequence generated, print it. 3) If proceed with a start as ‘true’ and recursively call GenAllSubset() with incremented ... Read More
You need to use MySQL event scheduler. It manages the execution of events as well as scheduling.First, you need to create a table. After that you can create a event that will schedule every single day.Let us create a table. The query to create a table is as follows −mysql> create table EventDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EventDateTime datetime -> ); Query OK, 0 rows affected (0.71 sec)Now you can insert some records in the table using insert command. The query ... Read More