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v5:reference:connection:genid

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v5:reference:connection:genid [2015/07/24 01:30]
mnewnham created
v5:reference:connection:genid [2016/03/20 02:11] (current)
mnewnham [Limitations]
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 </WRAP> </WRAP>
 ===== Description ===== ===== Description =====
-The function ''genId()'' is a useful, portable way of generation sequence numbers. **This is not the same as having an auto-increment row on a table**. It uses the best method available for a database, at best using the inbuilt sequencing functionality, and at the lowest end, maintaining a table with an integer field that is incremented using SQL syntax. +The function ''genId()'' is a useful, portable way of generation sequence numbers. **This is not the same as having an auto-increment row on a table**. If the requested sequence name does not exist, it automatically calls [[v5:reference:connection:createsequence|createSequence()]] to create it.It uses the best method available for a database, at best using the inbuilt sequencing functionality, and at the lowest end, maintaining a table with an integer field that is incremented using SQL syntax. 
  
 The optional parameters control the sequence name and the start number for the sequence. The return value is the sequence number. The optional parameters control the sequence name and the start number for the sequence. The return value is the sequence number.
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  */  */
 </code>  </code> 
 +===== Limitations =====
 +In databases that do not support sequences, they are emulated by insertion and updating table rows. Because the method provides no row locking, its use is not recommended in intense multi-user environments as duplicate sequence numbers may be returned. 
 +
  
v5/reference/connection/genid.1437694238.txt.gz · Last modified: 2017/04/21 11:35 (external edit)