2016年4月21日 · A surrogate key is typically a numeric value. Within SQL Server, Microsoft allows you to define a column with an identity property to help generate surrogate key values. …

2010年10月14日 · I want to get a particular table's primary key using SQL query for SQL Server database. In MySQL I am using following query to get table primary key: SHOW KEYS FROM …

2018年12月19日 · The trick to do this in a dynamic way is to look in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names and …

If the customer does not exist, you'll get an sql exception which text will be something like: null value in column "customer_id" violates not-null constraint (providing you made customer_id …

2008年12月3日 · Surrogate keys are the answer to some of the problems that natural keys have (propagating changes for example). As you get used to surrogates, it seems more clean, and …

2016年1月11日 · You defined the primary key twice. Try: CREATE TABLE SHIPPING_GRID( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'Unique ID for each row', …

Foreign Keys can improve (and hurt) performance. As stated here: Foreign keys boost performance. You should always create indexes on FK columns to reduce lookups. SQL …

2016年10月9日 · Disabling and Enabling All Foreign Keys. CREATE PROCEDURE pr_Disable_Triggers_v2 @disable BIT = 1 AS DECLARE @sql VARCHAR(500) , …

2014年1月29日 · You identify all the candidate keys during the design phase of a database system. During the implementation phase, you will decide on a primary key: either one of the …

2017年4月5日 · As regards "primary" keys. They are not a "special" type of key. A primary key is just any one candidate key of a table. There are at least two ways to create candidate keys in …