大约有 37,000 项符合查询结果（耗时：0.0250秒） [XML]
Add a column with a default value to an existing table in SQL Server
How can I add a column with a default value to an existing table in SQL Server 2000 / SQL Server 2005 ?
41 Answers
...
How to change a table name using an SQL query?
How can I in change the table name using a query statement?
10 Answers
10
...
How can you represent inheritance in a database?
...e SQL Entity-Attribute-Value antipattern. This is a brief overview:
Single Table Inheritance (aka Table Per Hierarchy Inheritance):
Using a single table as in your first option is probably the simplest design. As you mentioned, many attributes that are subtype-specific will have to be given a NULL v...
How do I UPDATE from a SELECT in SQL Server?
In SQL Server , it is possible to insert rows into a table with an INSERT.. SELECT statement:
35 Answers
...
How to delete a row by reference in data.table?
My question is related to assignment by reference versus copying in data.table . I want to know if one can delete rows by reference, similar to
...
Simple Pivot Table to Count Unique Values
This seems like a simple Pivot Table to learn with. I would like to do a count of unique values for a particular value I'm grouping on.
...
Eliminate extra separators below UITableView
When I set up a table view with 4 rows, there are still extra separators lines (or extra blank cells) below the filled rows.
...
How to drop column with constraint?
... problematic DEFAULT constraint, after that you can drop the column
alter table tbloffers drop constraint [ConstraintName]
go
alter table tbloffers drop column checkin
But the error may appear from other reasons - for example the user defined function or view with SCHEMABINDING option set for th...
How to force table cell content to wrap?
...
Use table-layout:fixed in the table and word-wrap:break-word in the td.
See this example:
<html>
<head>
<style>
table {border-collapse:collapse; table-layout:fixed; width:310px;}
table td {border:soli...
MySQL Error 1215: Cannot add foreign key constraint
... the keys I'm trying to use as a foreign key are primary keys in their own tables. I have done both of these things, if I'm not mistaken. Any other help you guys could offer?
...