questions about sql

How to save unique alphanumeric content in MySQL?

for example 100-character long ...

What is the purpose of views in SQL?

Possible Duplicate: What are views good for? I'm trying to figure out what the purpose of views in an SQL database is? Why, when and how would I create and use views? ...

sql

views

Oracle - delete where long like

How do you delete rows from a table, where a column contains a substring, but the type of that column is 'Long'. (Yes, I know I shouldn't use Long, but I'm maintaining someone else's mess). My first attempt was: delete from longtable where search_long(rowid) like '%hello%'; (following on from this answer) This returns: S...

Difference between JDBC Driver type numbers

I am very new to Java, when i was going through the JDBC section, i noticed that JDBC has different Drivers like Type 1 Driver Type 2 Driver etc.. to Type 4 Why did they get the name like Type 1, Type 2 etc.., Is there any logic? ...

SQL Server table design - don't want two records the same

One of the tables in my database has three columns. They are dt_id (PK), dt_name (varchar) and u_id (FK). dt_id is a identity column. But I want to have so that dt_name can only be once per user. So you can only put in " dt_name='CC', u_id=1 " once. How can I set the dt_name column so ? ----Edit:---- Sorry, i will explain better.....

sql

sql-server

How to BULK INSERT a file into a temporary table where the filename is a variable?

I have some code like this that I use to do a BULK INSERT of a data file into a table, where the data file and table name are variables: DECLARE @sql AS NVARCHAR(1000) SET @sql = 'BULK INSERT ' + @tableName + ' FROM ''' + @filename + ''' WITH (CODEPAGE=''ACP'', FIELDTERMINATOR=''|'')' EXEC (@sql) The works fine for standard tables, b...

Get SQL a Django model has (or would call) on .save()

How can you get the SQL for a Django model's .save(), i.e. from django.db import models class MyM(models.Model): text = models.TextField() How can you get the SQL that would be created/used in the following scenario: >>> m = MyM(text="123") >>> m.save() # What SQL Django just run? Thanks! ...

sql

django

django-models

How do I write this MySQL query to get the correct information? (Subquery, multiple subqueries)

Here is the query that I am working on: SELECT `unitid`, `name` FROM apartmentunits WHERE aptid = ( SELECT `aptid` FROM rentconditionsmap WHERE rentcondid = 1 AND condnum = 1 ) What I am having trouble figuring out is how to write this to add more rentcondition limiters to filter this list down more. SELECT `aptid` FROM rentcondi...

sql

mysql

Sql by hour starting at noon

I'm currently using a select statement with one column as DATEPART(hh, CallTime) AS Hour and then doing: GROUP BY DATEPART(hh, CallTime) ORDER BY Hour This displays the hours starting at midnight and going through midnight - how would I go about having this go from noon to noon? Thanks! ...

What kind of normalization rule does this violate?

Suppose I have two tables on a database, and they have 10 columns one and 11 columns the other, where 10 of the columns are exactly the same on both. What (if any) normalization rule am I violating? ...

sql

normalization

Question about join/update/insert sql query

I am working on making a new sqlite database. Obviously for a number of reasons, structure and organization is important. I have an existing database that is everything that I need, except for one column. So I duplicated the original db, and would like to just swap out that one column with new data from a different column in a different...

MYSQL query INNER JOIN two table

I have three tables CLASSES, CHILD_CLASSES, and STUDENTS. CLASSES looks like this (its self referencing): CLASS_ID | CLASS_PARENT | ------------------------- 1 | --- 2 | 1 3 | 2 CHILD_CLASSES looks like this: CC_ID | PARENT_CLASS_ID | CHILD_CLASS_ID ---------------------------------------- 1 ...

sql

mysql

Why wont this sort in Solr work?

I need to sort on a date-field type, which name is "mod_date". It works like this in the browser adress-bar: http://localhost:8983/solr/select/?&q=bmw&sort=mod_date+desc But I am using a phpSolr client which sends an URL to Solr, and the url sent is this: fq=+category%3A%22Bilar%22+%2B+car_action%3AS%C3%A4ljes&version=1....

Asp.net web site and web service hosting

I have a web site and a web service and I would like to host them somewhere. I need to use it mostly for testing and so that a some friends who are developing some applications to use the service have access to it. Also the service is using a MS SQL 2008 database. Could you suggest any good free or cheap web hosting service for this. I ...

converting ID to column name and also replacing NULL with last known value.

TABLE_A Rev ChangedBy ----------------------------- 1 A 2 B 3 C TABLE_B Rev Words ID ---------------------------- 1 description_1 52 1 history_1 54 2 description_2 52 3 history_2 54 Words column datatype is ntext. TABLE_C ID Name ----------------------------- 52 Description 54 Hi...

sql add or delete repeat row

I have an output like this: id name date school school1 1 john 11/11/2001 nyu ucla 1 john 11/11/2001 ucla nyu 2 paul 11/11/2011 uft mit 2 paul 11/11/2011 mit uft i will like to achieve this: id name date school school1 1 john 11/11/2001 nyu ucla 2 paul 11/11/2011 mit uft ...

Should I write a whole procedure for each database table.column I update separately?

I have an application that uses AJAX liberally. I have several places where a single database column is being updated for the record the user is actively editing. So far I've been creating separate stored procedures for each AJAX action... so I've got UPDATE_NAME, UPDATE_ADDRESS, UPDATE_PHONE stored procedures. I was just wondering if...

How can I get the SQL of a PreparedStatement?

I have a general Java method with the following method signature: private static ResultSet runSQLResultSet(String sql, Object... queryParams) It opens a connection, builds a PreparedStatement using the sql statement and the parameters in the queryParams variable length array, runs it, caches the ResultSet (in a CachedRowSetImpl), clos...

Ruby-on-Rails: How to pull out most recent entries from a limited subset of a database table

Imagine something like a model User who has many Friends, each of who has many Comments, where I'm trying to display to the user the latest 100 comments by his friends. Is it possible to draw out the latest 100 in a single SQL query, or am I going to have to use Ruby application logic to parse a bigger list or make multiple queries? I ...