Re: OT: SQL Data Type
What are the benefits on using a CHAR field versus VARCHAR? The basic idea, back to the first database systems, is that all records have the same length and use the same amount of space in the database. Thus finding a record is just a matter of multiplying this record length by the record number, and read a bunch of bytes: pretty fast. The problem is that database may grow pretty big if large fields are needed, and use much empty space, especially if many of the fields are empty, an empty field taking exactly as much space than a full field. Then came the VARCHAR, AKA memo field. The idea is to store this field in a special area where all fields have a specific length and occupy only the space they need. The database then stores the address of the data in the record, instead of the data itself, but the record still has the same length. The advantage of memo fields is more efficiency in terms of disk space used, but it also implies a two step process to retrieve data, then it is less efficient in terms of speed. It is then up to the programmer to decide what type of efficiency is the best for his application. General rules are: - the larger the field must be, - the more often this field can be empty, then the better it is to use VARCHAR. -- ___ REUSE CODE! Use custom tags; See http://www.contentbox.com/claude/customtags/tagstore.cfm (Please send any spam to this address: [EMAIL PROTECTED]) Thanks. ~| ColdFusion is delivering applications solutions at at top companies around the world in government. Find out how and where now http://www.adobe.com/cfusion/showcase/index.cfm?event=finderproductID=1522loc=en_us Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:293911 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4
Re: OT: SQL Data Type
On Wednesday 28 Nov 2007, Claude Schneegans wrote: It is then up to the programmer to decide what type of efficiency is the best for his application. However, almost no programmers will ever have to care about the tiny performance changes betwen the two, in which case VARCHAR is better because you don't need to TRIM() everything all the time. -- Tom Chiverton Helping to completely restore best-of-breed markets on: http://thefalken.livejournal.com This email is sent for and on behalf of Halliwells LLP. Halliwells LLP is a limited liability partnership registered in England and Wales under registered number OC307980 whose registered office address is at St James's Court Brown Street Manchester M2 2JF. A list of members is available for inspection at the registered office. Any reference to a partner in relation to Halliwells LLP means a member of Halliwells LLP. Regulated by The Solicitors Regulation Authority. CONFIDENTIALITY This email is intended only for the use of the addressee named above and may be confidential or legally privileged. If you are not the addressee you must not read it and must not use any information contained in nor copy it nor inform any person other than Halliwells LLP or the addressee of its existence or contents. If you have received this email in error please delete it and notify Halliwells LLP IT Department on 0870 365 2500. For more information about Halliwells LLP visit www.halliwells.com. ~| Download the latest ColdFusion 8 utilities including Report Builder, plug-ins for Eclipse and Dreamweaver updates. http;//www.adobe.com/cfusion/entitlement/index.cfm?e=labs%5adobecf8%5Fbeta Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:293913 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4
Re: OT: SQL Data Type
ColdFusion wrote: What are the benefits on using a CHAR field versus VARCHAR? Check your database manual, the differences between implementations are such that for every other answer is pure speculation. Jochem ~| ColdFusion is delivering applications solutions at at top companies around the world in government. Find out how and where now http://www.adobe.com/cfusion/showcase/index.cfm?event=finderproductID=1522loc=en_us Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:293914 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4
OT: SQL Data Type
What are the benefits on using a CHAR field versus VARCHAR? I know with a CHAR(10) field that if the data is: START then the actual value is: START_ _ _ _ _ rather than a VARCHAR(10) of START. ~| Create robust enterprise, web RIAs. Upgrade to ColdFusion 8 and integrate with Adobe Flex http://www.adobe.com/products/coldfusion/flex2/?sdid=RVJP Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:293905 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4
