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Articles on Trending Technologies
Technical articles with clear explanations and examples
How can I remove every column in a table in MySQL?
In order to remove every column in a table in MySQL, you can use DROP TABLE command. Following is the syntax:DROP TABLE yourTableName;Let us first create a table:mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentLastName varchar(20), StudentAge int, StudentAddress varchar(200), StudentCountryName varchar(30), StudentDateOfBirth datetime ); Query OK, 0 rows affected (0.85 sec)Let us check the description of table using DESC command:mysql> desc DemoTable;This will produce the following output:+--------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key ...
Read More8086 program to convert ASCII to BCD number
In this program we will see how to find the equivalent BCD number from an ASCII value.Problem StatementWrite 8086 Assembly language program to find the equivalent BCD number from an ASCII value. The number is stored at memory location 2050 and store the result at memory location 3050.DiscussionThis program can change ASCII value of a number to its BCD (Decimal) form. The ASCII values of the numbers are like below:ASCII (in Hex)30313233343536373839BCD00010203040506070809 From this table we can easily find that the last nibble of the ASCII value is actually the BCD equivalent. So to take the last nibble we have masked ...
Read MoreSelect query using MySQL IN() and avoid sorting in it
Using IN() sorts the result for the specific field. To avoid this, use ORDER BY and FIND_IN_SET() for the field.To understand the find_in_set(), let us create a table. The query to create a table is as follows −mysql> create table ProductStock -> ( -> ProductId int, -> ProductName varchar(20), -> ProductQuantity int, -> ProductPrice float -> ); Query OK, 0 rows affected (0.79 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into ProductStock values(1, 'Product-101', 10, 500.56); Query OK, 1 row affected (0.20 ...
Read MoreWhat is isThreadSafe attribute in JSP?
The isThreadSafe option marks a page as being thread-safe. By default, all JSPs are considered thread-safe. If you set the isThreadSafe option to false, the JSP engine makes sure that only one thread at a time is executing your JSP.The following page directive sets the isThreadSafe option to false −
Read MoreHow to process SQL statements with JDBC explain with an example?
To process an SQL statement, you need to follow the steps given below:Establish the connection.Create a statement.Execute the statement/query.Process the result.Close the connection.Establishing a ConnectionTo process SQL statements first of all you need to establish connection with the desired DBMS or, file System or, other data sources.To do so, Register the JDBC driver class, corresponding to the DataSource you need to the DriverManager using the registerDriver() method.Driver myDriver = new com.mysql.jdbc.Driver(); DriverManager.registerDriver(myDriver);This method accepts an object of the Driver class; it registers the specified Driver with the DriverManager.You can also register the driver using the forName() method. This method loads ...
Read MoreHow to add a where clause in a MySQL Insert statement?
You need to use UPDATE statement for this.The syntax is as followsupdate yourTableName set yourColumnName1=yourValue1, yourColumnName2=yourValue2, ....N where yourCondition;Let us create a table for our examplemysql> create table addWhereClauseDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(30), -> StudentPassword varchar(40) -> ); Query OK, 0 rows affected (0.45 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into addWhereClauseDemo(StudentName, StudentPassword) values('John', 'John123456'); Query OK, 1 row affected (0.14 sec) mysql> insert into addWhereClauseDemo(StudentName, StudentPassword) values('Carol', '99999'); Query OK, 1 row affected (0.24 sec) mysql> insert ...
Read MoreMySQL select accumulated (running sum) column?
To select accumulated column, let us first create a demo table. The query to create a table is as follows −mysql> create table accumulatedDemo -> ( -> Value int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into accumulatedDemo values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into accumulatedDemo values(15); Query OK, 1 row affected (0.09 sec) mysql> insert into accumulatedDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into accumulatedDemo values(25); Query OK, 1 row affected ...
Read MoreHow to use LocalBroadcastManager?
This example demonstrate about How to use LocalBroadcastManagerStep 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 text view to show broadcast values.Step 3 − Add the following code to src/MainActivity.java import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.pm.PackageManager; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v4.content.LocalBroadcastManager; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.TextView; public class MainActivity extends AppCompatActivity { TextView actionEvent; ...
Read MoreUpdate one column data to another column in MySQL if the second column is NOT NULL?
To update one column data to another column, you can use UPDATE command. Let us first create a table −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserFirstName varchar(20), ListOfName varchar(20) ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserFirstName, ListOfName) values('John', 'Larry'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable(UserFirstName, ListOfName) values('Carol', null); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(UserFirstName, ListOfName) values('David', 'Sam'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable(UserFirstName, ListOfName) ...
Read MoreDisplay the warning message when a FLOAT value is inserted into DECIMAL in MySQL?
You can create a temporary table with data type DECIMAL to get a warning when a float value is inserted into an int column. Display the same warning using SHOW WARNINGS.Let us create a table to understand. The query is as follows to create a table.mysql> create temporary table WarningDemo -> ( -> Value DECIMAL -> ); Query OK, 0 rows affected (0.13 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into WarningDemo values(9.80); Query OK, 1 row affected, 1 warning (0.03 sec)Here we are getting a warning. Let ...
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