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Добавлено: Ср Сен 17 2003 13:33 Заголовок сообщения: Такие вещи ищут не в инете, а в MSDN (+) |
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Visual FoxPro System Capacities
Some capacities may be limited by available memory.
Category Feature Number
Table and Index Files
Maximum # of records per table file 1 billion Maximum size of a table file 2 gigabytes Maximum # of characters per record 65,500 Maximum # of fields per record(1) 255 Maximum # of tables open at one time(2) 255 Maximum # of characters per table field 254 Maximum # of bytes per index key in a non-compact index(3) 100 Maximum # of bytes per index key in a compact index(3) 240 Maximum # of open index files per table(2) unlimited Maximum # of open indexes in all work areas(2) unlimited Maximum # of relations unlimited Maximum length of relational expressions unlimited
Field Characteristics
Maximum size of character fields 254 Maximum size of numeric (and float) fields 20 Maximum number of characters in field names in a free table 10 Maximum number of characters in field names in a table contained in a database 128 Minimum value of an integer -2,147,483,647 Maximum value of an integer 2,147,483,647 Digits of precision in numeric computations Visual FoxPro can handle numbers up to 9007199254740992 (2^53) in exact computations. 16 64 bits = 8 bytes Largest number = 10 ^ 308 = 2 ^ 1023 -> 10 bits per exponent + 1 for exp sign plus 1 for the number's sign => 12 bits. Leaving 52 bits for the mantissa + 1 for implied normalized bit -> 53 bits LOG10(2^53) = 15.95 decimal digits accuracy.
Variables and Arrays
Default # of variables 1,024 Maximum # of variables 65,000 Maximum # of arrays 65,000 Maximum # of elements per array 65,000
Program and Procedure Files
Maximum # of lines in source program files unlimited Maximum size of compiled program modules(4) 64K Maximum # of procedures per file unlimited Maximum # of nested DO calls 128 Maximum # of READ nesting levels 5 Maximum # of nested structured programming commands 384 Maximum # of passed parameters 27 Maximum # of transactions 5
Report Designer Capacities
Maximum # of objects in a report definition(2) unlimited Maximum length of a report definition 20 inches Maximum # of grouping levels 128 Maximum length of character report variables 255
Other Capacities
Maximum # of open windows (all types)(2) unlimited Maximum # of open Browse windows 255 Maximum # of characters per character string or memory variable 16,777,184 Maximum # of characters per command line 8,192 Maximum # of characters per label control on a report 252 Maximum # of characters per macro substituted line 8,192 Maximum # of open files System limit Maximum keystrokes in keyboard macro 1,024 Maximum fields that can be selected by a SQL SELECT statement 255 Maximum length of a string literal 255
1. If one or more fields allow null values, the limit is reduced by one t ... |
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