Generate Primary Key For Sql In Memory
How to create a specially formatted primary key in SQL Server 2005
Generate Primary Key For Sql In Memory Care
Jun 30, 2009 03:28 PMdso808LINK
I am creating a web app in c# using a SQL Server 2005 back-end. The problem: I have a screen that is entering a record into a table and I need the primary key to follow a special format. I was hoping to be able to set SQL Server's identity columns to simply auto-generate the primary key but I don't think I can with the format that I need. Here's the format: P##-####
OK, explanation - first there's the 'P' which is static and never changes. Then the first two '#'s - that would be the last 2 digits of the current year (i.e. for this year, '09'). Then after the '-', the last 4 '#'s are simply a counter which starts at '0001' at the beginning of each year and increments by '+1'.
Generate Primary Key For Sql In Memory Windows 7
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Summary: in this tutorial, you will learn how to use SQLite PRIMARY KEY constraint to define a primary key for a table. Introduction to SQLite primary key. A primary key is a column or group of columns used to identify the uniqueness of rows in a table. Each table has one and only one primary key. SQL Server: Primary Keys Learn how to create, drop, disable, and enable a primary key in SQL Server (Transact-SQL) with syntax and examples. What is a primary key in SQL Server? In SQL Server (Transact-SQL), a primary key is a single field or combination of fields that uniquely defines a record. Sql documentation: Create a Temporary or In-Memory Table. Example PostgreSQL and SQLite. To create a temporary table local to the session. Sep 26, 2007 The fact is, if the table var has 'primary key' set on the key (which honestly isn't really needed since its a table in memory), the sproc hangs (I let it run for about a 1/2 an hour).
Example: at the beginning of year 2009, the first record of 2009 would be entered with a primary key of 'P09-0001'. The second record entered would be 'P09-0002' and so on. Then, when year 2010 arrived, the first record of 2010 would have a primary key of 'P10-0001' and so on.
Does anyone have any recommendations on how best to accomplish this? If there is still a way to use the increment columns in SQL Server please let me know how because that seems to be the easiest way (less code the better). Also, I'm planning to use stored procedures for all data entry/updates in this app. Thanks in advance!
SQL Server 2005Primary KeySQL IDENTITYSQL Server 2005
Primary Key Generation Using Oracle's Sequence
Oracle provides the sequence
utility to automatically generate unique primary keys. To use this utility to auto-generate primary keys for a CMP entity bean, you must create a sequence table and use the @AutomaticKeyGeneration annotation to point to this table.
![Card Card](https://blog.sqlauthority.com/i/e/in-memory05.jpg)
In your Oracle database, you must create a sequence table that will create the primary keys, as shown in the following example:
This creates a sequences of primary key values, starting with 1, followed by 2, 3, and so forth. Easy driver pro key generator download. The sequence table in the example uses the default increment 1, but you can change this by specifying the increment keyword, such as increment by 3. When you do the latter, you must specify the exact same value in the cacheSize attribute of the @AutomaticKeyGeneration annotation:
If you have specified automatic table creation in the CMP bean's project settings, the sequence table will be created automatically when the entity bean is deployed. For more information, see @JarSettings Annotation. For more information on the definition of a CMP entity bean, see below.
Primary Key Generation Using SQL Server's IDENTITY
In SQL Server you can use the IDENTITY
keyword to indicate that a primary-key needs to be auto-generated. The following example shows a common scenario where the first primary key value is 1, and the increment is 1:
In the CMP entity bean definition you need to specify SQLServer(2000) as the type of automatic key generator you are using. You can also provide a cache size:
If you have specified automatic table creation in the CMP bean's project settings, the sequence table will be created automatically when the entity bean is deployed. For more information, see @JarSettings Annotation. For more information on the definition of a CMP entity bean, see below.
Primary Key Generation Using a Named Sequence Table
A named sequence table is similar to the Oracle sequence functionality in that a dedicated table is used to generate primary keys. However, the named sequence table approach is vendor-neutral. To auto-generate primary keys this way, create a named sequence table using the two SQL statements shown in the example:
In the CMP entity bean definition you need to specify the named sequence table as the type of automatic key generator you are using. You can also provide a cache size:
If you have specified automatic table creation in the CMP bean's project settings, the sequence table will be created automatically when the entity bean is deployed. For more information, see @JarSettings Annotation. For more information on the definition of a CMP entity bean, see the next section.
Note. When you specify a cacheSize value for a named sequence table, a series of unique values are reserved for entity bean creation. When a new cache is necessary, a second series of unique values is reserved, under the assumption that the first series of unique values was entirely used. This guarantees that primary key values are always unique, although it leaves open the possibility that primary key values are not necessarily sequential. For instance, when the first series of values is 10..20, the second series of values is 21-30, even if not all values in the first series were actually used to create entity beans.
Defining the CMP Entity Bean
When defining a CMP entity bean that uses one of the primary key generators, you use the the @AutomaticKeyGeneration annotation to point to the name of the primary key generator table to obtain primary keys. Also, you must define a primary key field of type Integer or Long to set and get the auto-generated primary key. However, the ejbCreate method does not take a primary key value as an argument. Instead the EJB container adds the correct primary key to the entity bean record.
The following example shows what the entity bean might look like. Notice that the bean uses the named sequence option described above, and that ejbCreate method does not take a primary key:Related Topics