Most voted "database" questions
A database (its abbreviation is BD, DB, database) is an organized collection of data typically used to model certain situations. Use this tag if you have questions about designing a database. If this is a specific database management system, like Mysql, for example, use this tag instead.
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answer65
viewsChanging customer information via ID
I cannot change customer information through ID Code that makes the changes in the Database public void Atualizar(Contato contato)//metodo para atualizar dados: update { OleDbParameter[] parametros…
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answers212
viewsRead column values - C#
I need to read the values of a column called Code_article and place them, only when the column is still empty, I execute and immediately gives the error: The object reference was not defined as an…
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answer82
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answer2224
viewsQuery the database through a text box
Hello, right now I’m in a part of a project where I have to do a database search through a text box. For example, he searched for "José" and returned all the data contained in the database with the…
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answer174
viewsError in getWritableDatabase()?
I’m doing a job for college. My project until a few minutes ago was working normally, inserting User and Book, but out of nowhere it started to give error in getWritableDatabase() and I have no idea…
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answers605
viewsTrigger updates only to 1 record
Considering the following trigger: CREATE TRIGGER tgr_vendas_d ON vendas FOR DELETE AS BEGIN DECLARE @valor DECIMAL(10,2), @data DATETIME; SELECT @data = d.data, @valor = d.valor FROM deleted d…
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answers99
viewsProcedure for storing in backup tables?
I have two tables, sales and salesProducts because of the volume of information in these tables reading/writing operations are slow. I need to create a database that stores this data (from the sales…
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answer30
viewsDoubt in the relations of the Eloquent - Laravel 5:2
Good afternoon sorry if I missed any similar question, I searched extensively both here and in English and found nothing like it, I have the following Model in the database contract id due_date…
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answers113
viewsHow to limit the amount of addresses a user may have in the database
I have a database, and I have the user table and the address table. I need to validate somehow so that a user can have at most 5 addresses in the registry. I use the Postgresql database and it is an…
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answers1807
viewsINNER JOIN with equal fields in a table - Error: #1066 - Not Unique table/alias: 'tb_usuario'
I have 3 tables as follows: At tb_usuario, I have two types of users (buyer, seller) in an ENUM field to differentiate the type of user. In the shopping cart I have the user Ids, product and…
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answer51
viewsDoubt about data type database
See this table of INT data types in SQL SERVER: tinyint | 0 a 255 | 1 byte smallint |-2^15 (-32.768) a 2^15-1 (32.767) | 2 bytes int |-2^31 (-2.147.483.648) a 2^31-1 (2.147.483.647) | 4 bytes About…
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answer441
viewsProcedure to create database and tables
I need to create a data bank for each client that makes a certain registration, for this I created a procedure to do such a thing. But I came across a small identification problem. When I run the…
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answers451
viewsDifficulty in relating the SNIS municipalities to those of IBGE
I’m trying to build a database that includes the population served by the sanitation service and the per capita GDP of each municipality. The first data I have already been able to access by SNIS.…
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answer219
viewsmysql Rank function grouped for a COUNT
I have 3 tables in MYSQL represented here as an example: I need a query that returns a RANK of contracts made grouped by commercial in a given period of time, for example: A query that returns the…
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answers309
viewsSelect in two tables with data from the first table?
In a table that contains some comments, one of the columns stores the ID of the user who made this comment, how can I recover the data of that user with the ID at the time of making a query in the…
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answer155
viewsQueries Builder Problems (Query Builder) in Laravel 4.2
Hello, I’m having trouble generating a querie using the Querie Builder of Laravel 4.2, the difficulty arises from the need that the resulting sentences for search in the database are within…
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answers4016
viewsCreating more than one Android Studio table (Sqlite)
I’m trying to develop a mobile app for a final job of my college, it’s pretty simple! The application has to save the information registered in the database. However I would have to create 4…
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answers137
viewsComparison of geographical points in postgres
I have a structure like this: A table veiculo where I store the id and the placa of the vehicle. A table estacionamento where I store the nome do estacionamento, the id and the area of him (a…
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answers33
viewsWhat is a database? What is it for?
I’m rehearsing my studies in information systems and I’m curious about the subject!
databaseasked 7 years, 5 months ago Eudivan Oliveira 11 -
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answer2025
viewsPick up records with date greater than the current - Laravel 5.1
I need to list the schedules that have date greater or equal to the current date, I am doing the way below but does not work, it does not return any record.…
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answer362
viewsSplit the table in two?
I have a table with 25 columns (counting the FK) and two groups of users, one will access only 10 columns and the other will access almost all. Because I thought I had many columns in a single table…
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answers509
viewsCapture values from one table and insert them into another
I have a temporary table that fills it with the result of a particular query. Now I need to go through the data of this temporary table, row by row, and take certain fields and insert them into…
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answers101
viewsRelationship between tables
I have a certain table already created and populated: CREATE TABLE `formulario` ( `id` int(4) NOT NULL AUTO_INCREMENT, `nome` varbinary(50) DEFAULT NULL, `carteira` varchar(30) NOT NULL,…
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answers40
viewsHow does optimistic competition work?
In an application with pessimistic competition there is data containment usually involving Locking mechanisms. In optimistic competition no. Two clients can try to write but only one can. What are…
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answer1636
viewsHow to make a query per day, week, month period in Mysql
How do I query for period, day, week, month in Mysql? for example I would like to display data filtered by periods example display data yesterday, last week, two weeks, three weeks, a month ago and…
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answers2803
viewsFile storage, database or disk?
I am developing an intranet system, with a file storage module (exclusively PDF). What you tell me about the storage location, save to disk on the server or in a database? Remembering that it is an…
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answer288
viewsError while trying to connect bd MSSQL Server using PDO
I cannot access the MS SQL SERVER database using PDO. I’ve done everything, the best answer I could was with the code below, but I keep getting an error reply: SQLSTATE[] Connection Error (null)…
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answers71
viewsGlobal variable or database always
I made an application using jQuery Mobile library, it is an application to split account. I created a main object called conta and it is incremented according to the user’s actions (code below). As…
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viewsReturning information recorded in the bank
I have a system that is installed on an unstable network, my doubt is the following, if at some point in my recording I lose the connection to the database, how do I undo what was done in the…
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answers952
viewsSql command does not run via php
I’m having a problem with my bd query. I want to make a login page with the following form: <form method="post" action="Login.php"> Email:<br> <input class="form-control"…
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answer1339
viewsPostgresql - Inserting data into linked tables by Foreign Key
Hello! I’m having a problem inserting data into tables linked by a foreign key. I read in some places that there is a command "with" that helps in these situations, but I didn’t understand how to…
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answer208
viewsHow to Save an Image to the Database
Hi, I was wondering if you have how to save an image in the database and show in a listview. If you have how you wanted to know or if there is no way to save an image in the database , how can I…
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answers2073
viewsError creating Mysql Relations using Wampserver
I built the entire database and now I’m trying to do the relations, when I click on the primary key (referential) and click on the foreign key, the following error appears: "Error: Relational…
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answer40
viewsError changing old database data
With the help of this reply I was able to edit the data I enter in the database, but the old data that is already registered, when I try to change the registration, the program continues to close…
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answer364
viewsHow to grab the value stored in a column using Cursor?
I have a cursor that receives all data from my table then use the Simplescursoradapter to put in a listview. I was wondering if with this same cursor I could take a die from a Row and put in a…
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answer1580
viewsRecover database from . frm and . idb files
My backup got incomplete and corrupted my ibdata database, now my database does not access my tables. Keeps giving error! I don’t care about the data! But I really need the structure of the tables.…
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viewsSums and Reformatting db for a Datagridview
I probably did not draw up a correct title, but I will try to explain my very detailed question. I’m working with Windowsform at Visualbasic15 I need to make a form where I get data from a tb in a…
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answer1207
viewsMysql error 2002 connection refused
I hosted a website on 007gb.with and I’m trying to access my remote database but I get the message "Mensagem do erro: SQLSTATE[HY000] [2002] Connection refused Code: 2002 Fatal error: Call to a…
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answer524
viewsBackup and Restor Mongodb - ways
I’m starting in mongodb, linux platform. would like to know what the best backup strategy since: Data import and Export - are used for cvs or json outputs Mongodump and Mongorestore - are used for…
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answers389
viewsError when connecting to Mysql database using C# application in Visual Studio
Hello, I created the registration form and at the time I will save the text box items in the database of the following error 'Host 'DESKTOP_R70LLO is not allowed to connect to this Mysql server'. By…
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answers1020
viewsDelete record being duplicated in query with Inner Join
I am making a query to my database and in this query I use an INNER JOIN to join two tables! But I have a problem, because I do not know how to manipulate JOIN very well, and this is generating a…
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answers851
viewsDatabase connection - PDO
Guys, in the course, we are manipulating database with PDO, but now in the connection part, appeared to me the MYSQL_ATTR_INIT_COMMAND and I don’t really understand what it’s for, I just know that…
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answer84
viewsMYSQLI error with _GET attribute - Fatal error: Call to a Member Function error() on a non-object in
I got a problem and I don’t know how to fix it. I am using MYSQLI to query a database using GET to get the name of the table where the query should be made. BD connection code: $hostbd =…
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answers57
viewsHow to make a select that returns the expected result
Hello, I have 3 tables in Mysql Categorias,VideoContemCategoria and Videos I’m trying to make a select where I return all categories and together with each category return the last video that was…
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answer219
viewsQuery in date column with current week filter
I’ve been looking for a mysql command that does such a function. The purpose of this is that I have to display a current week’s item schedule. From Sunday to Saturday. Is there a query that makes…
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answer56
viewsReturning the NULL value
Someone can help me, I’m making a code to insert data into a table in the database and update too, but unfortunately it’s not working, all variables are giving NULL and the very code that selects…
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answers128
viewsVisual Studio Installer Projects with Postgresql
I am starting a Windows Form C#project, a commercial application that the user downloads, installs and uses, without complications. It is possible to configure Visual Studio Installer Projects to…
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answers1538
viewsHow to insert the data into a specific field of a _mysql_table?
I have a table called company, with the fields name, addressee, city, telephone, email and link. How should I proceed to enter a value in the field link that is empty?…