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Articles by karthikeya Boyini
Page 121 of 143
Create an aggregate checksum of a column in MySQL
You can use CRC32 checksum for this. The syntax is as follows −SELECT SUM(CRC32(yourColumnName)) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table CRC32Demo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserId varchar(20) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into CRC32Demo(UserId) values('USER-1'); Query OK, 1 row affected (0.38 sec) mysql> insert into CRC32Demo(UserId) values('USER-123'); Query OK, 1 row ...
Read MoreCan we have a switch statement in JSP for XPath expression?
The tag works like a Java switch statement. With this, you can choose between a number of alternatives. Where the switch statement has the case statements, the tag has the tags. In a similar way, a switch statement has the default clause to specify a default action and the tag has the tag as the default clause.AttributeThe tag does not have any attribute.The tag has one attributes which is listed below.The tag does not have any attribute.The tag has the following attributes −AttributeDescriptionRequiredDefaultselectCondition to evaluateYesNoneExample ...
Read MoreDeclare syntax error in MySQL Workbench?
The DECLARE syntax must between BEGIN and END. The syntax is as follows −BEGIN DECLARE yourVariableName1 dataType, DECLARE yourVariableName2 dataType, . . . . ENDHere is the query to avoid DECLARE syntax error in MySQL −mysql> DELIMITER // mysql> create procedure declare_Demo() -> BEGIN -> DECLARE Name varchar(100); -> SET Name: ='John'; -> SELECT Name; -> END -> // Query OK, 0 rows affected (0.17 sec) mysql> DELIMITER ;Call the stored procedure with the help of CALL command. The syntax is as follows −CALL yourStoredProcedureName();The query is as follows −mysql> call declare_Demo();The following is ...
Read MoreWhat does a “set+0” in a MySQL statement do?
The set+0 converts the set value to integer. Let us see an example by creating a table −mysql> create table SetZeroDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> TechnicalSkills set('C', 'Spring Framework /Hibernate', 'Python', 'Django Framework', 'Core Java') NOT NULL -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SetZeroDemo(TechnicalSkills) -> values('C, Spring Framework /Hibernate, Python, Django Framework, Core Java'); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement. The ...
Read MoreHow can I create custom tag in JSP which can accept attribute from parent jsp page?
You can use various attributes along with your custom tags. To accept an attribute value, a custom tag class needs to implement the setter methods, identical to the JavaBean setter methods as shown below −package com.tutorialspoint; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; import java.io.*; public class HelloTag extends SimpleTagSupport { private String message; public void setMessage(String msg) { this.message = msg; } StringWriter sw = new StringWriter(); public void doTag() throws JspException, IOException { if (message != null) { /* Use message from attribute ...
Read MoreHow can I set a MySQL database to use MyISAM by default?
To set the default storage engine, use the following syntax −set @@default_storage_engine = ’yourEngineType’;Now implement the above syntax to set the default engine to MyISAM. The query is as follows −mysql> set @@default_storage_engine = 'MyISAM'; Query OK, 0 rows affected (0.05 sec)Now you can check the default engine type with the help of SELECT statement. The query is as follows −mysql> select @@default_storage_engine;The following is the output displaying the engine as MyISAM −+--------------------------+ | @@default_storage_engine | +--------------------------+ | MyISAM | +--------------------------+ 1 ...
Read MoreGet the number of days between current date and date field?
To get the number of days between current date and date field, the syntax is as follows −SELECT DATEDIFF(CURDATE(), STR_TO_DATE(yourColumnName, '%d-%m-%Y')) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table DateDifferenceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ArrivalDate varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into DateDifferenceDemo(ArrivalDate) values('12-10-2011'); Query OK, 1 row affected (0.14 sec) mysql> insert ...
Read MoreRead/Write structure to a file using C
fwrite() and fread() is used to write to a file in C.fwrite() syntaxfwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)whereptr - A pointer to array of elements to be writtensize - Size in bytes of each element to be writtennmemb - Number of elements, each one with a size of bytesstream – A pointer to a FILE object that specifies an output streamfread() syntaxfread(void *ptr, size_t size, size_t nmemb, FILE *stream)whereptr - A pointer to a block of memory with a minimum size of size*nmemb bytes.size - Size in bytes of each element to be read.nmemb - Number of ...
Read MoreC++ Program to Implement Hash Tables
A hash table is a data structure which is used to store key-value pairs. Hash function is used by hash table to compute an index into an array in which an element will be inserted or searched.This is a C++ program to Implement Hash Tables.AlgorithmBegin Initialize the table size T_S to some integer value. Create a structure hashTableEntry to declare key k and value v. Create a class hashMapTable: Create a constructor hashMapTable to create the table. Create a hashFunc() function which return key mod T_S. Create a function Insert() to insert element at ...
Read MoreDoes MySQL support table inheritance?
MySQL uses foreign key constraint instead of inheritance. MySQL does not support table inheritance.You can achieve the same with the help of foreign key constraint. Let us create a table and use the foreign key constraint. The query to create the first table is as follows −mysql> create table Parent_Table -> ( -> ParentId int, -> PRIMARY KEY(ParentId) -> ); Query OK, 0 rows affected (3.59 sec)Now create the second table. The query to create the second table is as follows −mysql> create table Child_Table ...
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