mysql

Mysql - Preventing duplicate entries of combined columns with Unique Index

由 。_饼干妹妹 提交于 2021-02-16 14:58:50
问题 I have an issue with duplicate entries in a database and due to the nature of the problem the easiest way to fix it would be to remove current duplicate rows and prevent further duplicates from being added . Here is the table structure : | a | b | c | user url1 token1 photo url1 token2 action action1 token3 user url1 token4 photo url1 token5 action action2 token6 I want to prevent duplicate entries only when 2 columns are duplicated, in this case a and b . So here we have user | url1 and

How to send the my sql result to controller in codeigniter as a variable

由 為{幸葍}努か 提交于 2021-02-16 14:58:27
问题 In my mode I am selecting a field as $query1 = $this->db->query("SELECT dPassword FROM tbl_login WHERE dEmailID='a@a.in'"); How to return dpassword as a variable to my controller I tried this way return dpassword; 回答1: The following is also fine: if($query1->num_rows() > 0){ $row = $query1->row(); } return $row->dPassword; Then if your query was to return more than a single row you could operate on the results like so: foreach($query1->result() as $row){ echo $row->field1; echo $row->field2;

Mysql - Preventing duplicate entries of combined columns with Unique Index

由 二次信任 提交于 2021-02-16 14:57:25
问题 I have an issue with duplicate entries in a database and due to the nature of the problem the easiest way to fix it would be to remove current duplicate rows and prevent further duplicates from being added . Here is the table structure : | a | b | c | user url1 token1 photo url1 token2 action action1 token3 user url1 token4 photo url1 token5 action action2 token6 I want to prevent duplicate entries only when 2 columns are duplicated, in this case a and b . So here we have user | url1 and

How to send the my sql result to controller in codeigniter as a variable

由 ﹥＞﹥吖頭↗ 提交于 2021-02-16 14:56:45
问题 In my mode I am selecting a field as $query1 = $this->db->query("SELECT dPassword FROM tbl_login WHERE dEmailID='a@a.in'"); How to return dpassword as a variable to my controller I tried this way return dpassword; 回答1: The following is also fine: if($query1->num_rows() > 0){ $row = $query1->row(); } return $row->dPassword; Then if your query was to return more than a single row you could operate on the results like so: foreach($query1->result() as $row){ echo $row->field1; echo $row->field2;

Java DB connection

由 混江龙づ霸主 提交于 2021-02-16 14:28:47
问题 I have a java project with many files that connects to the database. Can anyone tell me if it is possible to use a java class file for connecting to the database so that I won't create a Database connection for every file and please teach me how.. thanks for the help :D Here's the code I used but it didn't work dbConnect.java - class file public class dbConnect { public static void connect(){ Connection conn; Statement stmt; ResultSet rs; String sql; conn = null; String url = "jdbc:mysql:/

ClassNotFoundException in JDBC program despite of adding driver's JAR file [duplicate]

由 蹲街弑〆低调 提交于 2021-02-16 14:20:51
问题 This question already has answers here : Connect Java to a MySQL database (14 answers) Closed 10 days ago . I am writing a simple program in Java using to demonstrate insertion of data in MySQL table using JDBC. But the program is generating ClassNotFoundException while registering driver. import java.sql.*; public class test { public static void main(String[] args) { try { Class.forName("com.mysql.jdbc.Driver"); } catch(ClassNotFoundException e) { System.out.println("ClassNotFoundException:

Error connecting to database: (using class org.gjt.mm.mysql.Driver)

由 走远了吗. 提交于 2021-02-16 13:54:48
问题 I am trying to set up a connection in Pentaho 5.3.0.0-213 to mysql on localhost. I am using a Mac running OS 10.10.2. I can connect to the DB using Sequel Pro and have read through all the answers already given on this site (and others!) and have downloaded and copied mysql-connector-java-5.1.34-bin.jar to data-integration/lib and still get the same error. Any suggestions would be welcome. The whole error message is as follows: Error connecting to database [localhost_con] : org.pentaho.di

MySQL application users vs database users

由 别等时光非礼了梦想. 提交于 2021-02-16 13:43:47
问题 Unfortunately this question may be a little broad, because I can't work out the proper terms to help me bring all this together. I'm very new to php/SQL, and I'm attempting to set up a minimal site with very simple login/register functionality. Should I be creating a new database user whenever I register a new web user? Are CRUD privileges safe to give to all users of the website? Should I actually make a DB user for registering, one which can only insert into the user table and nothing else

Mysql index on view not working

由 六眼飞鱼酱① 提交于 2021-02-16 13:28:09
问题 I created a view named 'myview' as below. create view myview as select 'a' source,col1,col2 from table_a union select source,col1,col2 from table_b ; table_a has an index on col1 , table_b has an index on source , col1 . When I query on myview as below, no index is used. select * from myview where source = a and col1 = 'xxx' ; How do I make the indexes work on this query? Create Code CREATE TABLE `table_a` ( `col1` VARCHAR(50) NULL DEFAULT NULL, `col2` VARCHAR(50) NULL DEFAULT NULL, INDEX

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由 六眼飞鱼酱① 提交于 2021-02-16 13:10:31
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