I’m currently writing a data access layer for an application. The access layer makes extensive use of linq classes to return data. Currently in order to reflect data back to the database I’ve added a private data context member and a public save method. The code looks something like this: private DataContext myDb; public static … Read more
I have a table called countries and I define the country_name column to be unique by creating a “Index/Key” of type “Unique Key” on SQL Server 2008 R2. But I have the following questions: will creating “Index/Key” of type “Unique Key” automatically create a non-clustered index on this column? if I change the type from … Read more
I’m trying to update a field in the database to the sum of its joined values: UPDATE P SET extrasPrice = SUM(E.price) FROM dbo.BookingPitchExtras AS E INNER JOIN dbo.BookingPitches AS P ON E.pitchID = P.ID AND P.bookingID = 1 WHERE E.[required] = 1 When I run this I get the following error: “An aggregate may … Read more
Is there any way to clear the Client Statistics table in Microsoft SQL Server Management Studio (2008 R2) besides create a new query? Answer Go to the “Query” menu then choose “Reset Client Statistics”. You can customise the toolbar to add this function if you require it frequently. AttributionSource : Link , Question Author : … Read more
I am a noob when it comes to SQL syntax. I have a table with lots of rows and columns of course 😛 Lets say it looks like this: AAA BBB CCC DDD ———————– Row1 | 1 A D X Row2 | 2 B C X Row3 | 3 C D Z Now I want … Read more
I am trying to drop a column from a table. How can I check if the column exists or not? I went through the documentation at https://www.postgresql.org/docs/9.2/static/sql-altertable.html, but didn’t find any example how to do it. Even found How to check if a column exists in a SQL Server table?, but it does not seem … Read more
I am learning about databases and SQL for the first time. In the text I’m reading (Oracle 11g: SQL by Joan Casteel), it says that “many-to-many relationships can’t exist in a relational database.” I understand that we are to avoid them, and I understand how to create a bridging entity to eliminate them, but I … Read more
There is a nice feature in ADO.NET that allows you to send multiple SQL statements to database in one roundtrip and receive results for all statements: var command = new SqlCommand(“SELECT count(*) FROM TableA; SELECT count(*) FROM TableB;”, connection); using(var reader = command.ExecuteReader()) { reader.Read(); resultA = reader.GetInt32(0); reader.NextResult(); reader.Read(); resultB = reader.GetInt32(0); } Is … Read more
I get an error on the following Python code: import mysql.connector cnx = mysql.connector.connect(user=’root’, password=”, host=’127.0.0.1′, database=’DB’) cursor = cnx.cursor() Name = “James” Department = “Finance” StartYear = 2001 CurrentPos = 2001 Link = “” add_user = (“INSERT INTO DB.tbluser ” “(username, department, startyear, currentpos, link) ” “VALUES (%s, %s, %d, %d, %s)”) data_user = … Read more
I have two arrays: Question and UserProfile The userProfiles: [] array contain { id, name } objects The questions: [] array contains { id, text, createdBy } objects The createdBy integer in questions is always one of the id values in userProfiles. Is there a way I could “join” the arrays in much the same … Read more
