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cstokes91
Yak Posting Veteran
72 Posts |
 Posted - 2013-05-02 : 12:30:50
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| Hey,I have a random question... When you write a query... say SELECT* FROM [DatabaseName].[dbo].[TableName] what is the difference in that and [DatabaseName]..[TableName] ? I have seen it written like that before but I just don't want to run into errors later down the road for not fully qualifying or something. I have even ran into weird errors from not putting the brackets around the database and table names. |
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James K
Master Smack Fu Yak Hacker
3873 Posts |
Posted - 2013-05-02 : 12:36:54
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| The 3-part naming convention is [Databasename].[SchemaName].[TableName]. When you omit the [Schemaname], it assumes the schema is the default schema (in your example dbo).So most of the time, you could omit the schema name, but I always specify the actual schema name. |
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jeffw8713
Aged Yak Warrior
819 Posts |
Posted - 2013-05-02 : 13:01:56
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| If you omit the schema name - it could cause performance issues. When you omit the schema - and you have multiple users using that query to access the system and each user has a different default schema, SQL Server will create a separate execution plan for each user.Not only could you have multiple plans defined and saved in memory, but one user could end up with an optimal plan and a different user with a non-optimal plan and troubleshooting will become much harder.I recommend that you always schema-qualify all objects and only use the database when accessing objects in another database. |
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Difference in Querying Data