GNU Info
(slib.info)Table Operations
Table Operations
----------------
These are the descriptions of the methods available from an open
relational table. A method is retrieved from a table by calling the
table with the symbol name of the operation. For example:
(define telephone-table-desc
((my-database 'create-table) 'telephone-table-desc))
(require 'common-list-functions)
(define ndrp (telephone-table-desc 'row:insert))
(ndrp '(1 #t name #f string))
(ndrp '(2 #f telephone
(lambda (d)
(and (string? d) (> (string-length d) 2)
(every
(lambda (c)
(memv c '(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9
#\+ #\( #\ #\) #\-)))
(string->list d))))
string))
Some operations described below require primary key arguments. Primary
keys arguments are denoted KEY1 KEY2 .... It is an error to call an
operation for a table which takes primary key arguments with the wrong
number of primary keys for that table.
The term "row" used below refers to a Scheme list of values (one for
each column) in the order specified in the descriptor (table) for this
table. Missing values appear as `#f'. Primary keys must not be
missing.
- Function: get column-name
Returns a procedure of arguments KEY1 KEY2 ... which returns the
value for the COLUMN-NAME column of the row associated with
primary keys KEY1, KEY2 ... if that row exists in the table, or
`#f' otherwise.
((plat 'get 'processor) 'djgpp) => i386
((plat 'get 'processor) 'be-os) => #f
- Function: get* column-name
Returns a procedure of optional arguments MATCH-KEY1 ... which
returns a list of the values for the specified column for all rows
in this table. The optional MATCH-KEY1 ... arguments restrict
actions to a subset of the table. See the match-key description
below for details.
((plat 'get* 'processor)) =>
(i386 8086 i386 8086 i386 i386 8086 m68000
m68000 m68000 m68000 m68000 powerpc)
((plat 'get* 'processor) #f) =>
(i386 8086 i386 8086 i386 i386 8086 m68000
m68000 m68000 m68000 m68000 powerpc)
(define (a-key? key)
(char=? #\a (string-ref (symbol->string key) 0)))
((plat 'get* 'processor) a-key?) =>
(m68000 m68000 m68000 m68000 m68000 powerpc)
((plat 'get* 'name) a-key?) =>
(atari-st-turbo-c atari-st-gcc amiga-sas/c-5.10
amiga-aztec amiga-dice-c aix)
- Function: row:retrieve
Returns a procedure of arguments KEY1 KEY2 ... which returns the
row associated with primary keys KEY1, KEY2 ... if it exists, or
`#f' otherwise.
((plat 'row:retrieve) 'linux) => (linux i386 linux gcc)
((plat 'row:retrieve) 'multics) => #f
- Function: row:retrieve*
Returns a procedure of optional arguments MATCH-KEY1 ... which
returns a list of all rows in this table. The optional MATCH-KEY1
... arguments restrict actions to a subset of the table. See the
match-key description below for details.
((plat 'row:retrieve*) a-key?) =>
((atari-st-turbo-c m68000 atari turbo-c)
(atari-st-gcc m68000 atari gcc)
(amiga-sas/c-5.10 m68000 amiga sas/c)
(amiga-aztec m68000 amiga aztec)
(amiga-dice-c m68000 amiga dice-c)
(aix powerpc aix -))
- Function: row:remove
Returns a procedure of arguments KEY1 KEY2 ... which removes and
returns the row associated with primary keys KEY1, KEY2 ... if it
exists, or `#f' otherwise.
- Function: row:remove*
Returns a procedure of optional arguments MATCH-KEY1 ... which
removes and returns a list of all rows in this table. The optional
MATCH-KEY1 ... arguments restrict actions to a subset of the
table. See the match-key description below for details.
- Function: row:delete
Returns a procedure of arguments KEY1 KEY2 ... which deletes the
row associated with primary keys KEY1, KEY2 ... if it exists. The
value returned is unspecified.
- Function: row:delete*
Returns a procedure of optional arguments MATCH-KEY1 ... which
Deletes all rows from this table. The optional MATCH-KEY1 ...
arguments restrict deletions to a subset of the table. See the
match-key description below for details. The value returned is
unspecified. The descriptor table and catalog entry for this
table are not affected.
- Function: row:update
Returns a procedure of one argument, ROW, which adds the row, ROW,
to this table. If a row for the primary key(s) specified by ROW
already exists in this table, it will be overwritten. The value
returned is unspecified.
- Function: row:update*
Returns a procedure of one argument, ROWS, which adds each row in
the list of rows, ROWS, to this table. If a row for the primary
key specified by an element of ROWS already exists in this table,
it will be overwritten. The value returned is unspecified.
- Function: row:insert
Adds the row ROW to this table. If a row for the primary key(s)
specified by ROW already exists in this table an error is
signaled. The value returned is unspecified.
- Function: row:insert*
Returns a procedure of one argument, ROWS, which adds each row in
the list of rows, ROWS, to this table. If a row for the primary
key specified by an element of ROWS already exists in this table,
an error is signaled. The value returned is unspecified.
- Function: for-each-row
Returns a procedure of arguments PROC MATCH-KEY1 ... which calls
PROC with each ROW in this table in the (implementation-dependent)
natural ordering for rows. The optional MATCH-KEY1 ... arguments
restrict actions to a subset of the table. See the match-key
description below for details.
_Real_ relational programmers would use some least-upper-bound join
for every row to get them in order; But we don't have joins yet.
The (optional) MATCH-KEY1 ... arguments are used to restrict actions of
a whole-table operation to a subset of that table. Those procedures
(returned by methods) which accept match-key arguments will accept any
number of match-key arguments between zero and the number of primary
keys in the table. Any unspecified MATCH-KEY arguments default to `#f'.
The MATCH-KEY1 ... restrict the actions of the table command to those
records whose primary keys each satisfy the corresponding MATCH-KEY
argument. The arguments and their actions are:
`#f'
The false value matches any key in the corresponding position.
an object of type procedure
This procedure must take a single argument, the key in the
corresponding position. Any key for which the procedure
returns a non-false value is a match; Any key for which the
procedure returns a `#f' is not.
other values
Any other value matches only those keys `equal?' to it.
- Function: close-table
Subsequent operations to this table will signal an error.
- Constant: column-names
- Constant: column-foreigns
- Constant: column-domains
- Constant: column-types
Return a list of the column names, foreign-key table names, domain
names, or type names respectively for this table. These 4 methods
are different from the others in that the list is returned, rather
than a procedure to obtain the list.
- Constant: primary-limit
Returns the number of primary keys fields in the relations in this
table.
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