GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
RedHat 5.2(Apollo) |
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declare(l) |
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declare - declare a cursor
declare [ binary ] cursor for select statement
Declare allows a user to create cursors. Cursors are only available in transactions.
Normal cursors return data back in ASCII format. Since data is stored natively in binary format, the system must do a conversion to produce the ASCII format. In addition, ASCII formats are often larger in size than binary format. Once the attributes come back in ASCII, often the client application then has to convert it to a binary format to manipulate it anyway.
Binary cursors give you back the data in the native binary representation. Thus, binary cursors will tend to be a little faster since there’s less overhead of conversion.
However, ASCII is architectural neutral whereas binary representation can differ between different machine architecture. Thus, if your client machine uses a different representation than you server machine, getting back attributes in binary format is probably not what you want. Also, if your main purpose is displaying the data in ASCII, then getting it back in ASCII will save you some effort on the client side.
For an example, see the fetch(l) manual page.
fetch(l), begin(l), commit(l), select(l).
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declare(l) | |