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How to check if a column exists in a SQL Server table?

... SQL Server 2005 onwards: IF EXISTS(SELECT 1 FROM sys.columns WHERE Name = N'columnName' AND Object_ID = Object_ID(N'schemaName.tableName')) BEGIN -- Column Exists END Martin Smith's version is shorter: IF COL_LENGTH('schemaName.tabl...
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How do I check if an index exists on a table field in MySQL?

... Try: SELECT * FROM information_schema.statistics WHERE table_schema = [DATABASE NAME] AND table_name = [TABLE NAME] AND column_name = [COLUMN NAME] It will tell you if there is an index of any kind on a certain column wi...
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Hibernate Criteria returns children multiple times with FetchType.EAGER

....class) .list(); List result = session.createQuery("select o from Order o left join fetch o.lineItems").list(); All of these examples produce the same SQL statement: SELECT o.*, l.* from ORDER o LEFT OUTER JOIN LINE_ITEMS l ON o.ID = l.ORDER_ID Want to know why th...
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Replacement for “rename” in dplyr

... The next version of dplyr will support an improved version of select that also incorporates renaming: > mtcars2 <- select( mtcars, disp2 = disp ) > head( mtcars2 ) disp2 Mazda RX4 160 Mazda RX4 Wag 160 Datsun 710 108 Hornet 4 Drive 258 H...
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How to drop column with constraint?

...ing of constraints script: DECLARE @sql NVARCHAR(MAX) WHILE 1=1 BEGIN SELECT TOP 1 @sql = N'alter table tbloffers drop constraint ['+dc.NAME+N']' from sys.default_constraints dc JOIN sys.columns c ON c.default_object_id = dc.object_id WHERE dc.parent_object_id = OBJ...
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Get cursor position (in characters) within a text Input field

... Easier update: Use field.selectionStart example in this answer. Thanks to @commonSenseCode for pointing this out. Old answer: Found this solution. Not jquery based but there is no problem to integrate it to jquery: /* ** Returns the caret (curs...
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Why do we always prefer using parameters in SQL statements?

I am very new to working with databases. Now I can write SELECT , UPDATE , DELETE , and INSERT commands. But I have seen many forums where we prefer to write: ...
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How can I disable the UITableView selection?

When you tap a row in a UITableView , the row is highlighted and selected. Is it possible to disable this so tapping a row does nothing? ...
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Joining three tables using MySQL

... Simply use: select s.name "Student", c.name "Course" from student s, bridge b, course c where b.sid = s.sid and b.cid = c.cid share | ...
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Open directory dialog

I want the user to select a directory where a file that I will then generate will be saved. I know that in WPF I should use the OpenFileDialog from Win32, but unfortunately the dialog requires file(s) to be selected - it stays open if I simply click OK without choosing one. I could "hack up" the f...