1grass-dbf(1)                  Grass User's Manual                 grass-dbf(1)
2
3
4
5DBF driver in GRASS
6

Creating a DBF table

8       Usually  DBF  tables  are created by GRASS when generating a vector map
9       with attribute (and using DBF as default attribute driver).
10
11       If a DBF table has to be created manually, db.execute can be used or  a
12       spreadsheet application. Also db.copy is sometimes useful.
13

Supported SQL commands by DBF driver

15
16         ALTER TABLE table ADD [COLUMN] columndef
17         CREATE TABLE table ( columndefs )
18         DROP TABLE table
19         SELECT columns FROM table
20         SELECT columns FROM table WHERE condition
21         DELETE FROM table
22         DELETE FROM table WHERE condition
23         INSERT INTO table VALUES (value1[,value2,...])
24         INSERT     INTO    table    (    column1[,column2,...]    )    VALUES
25       (value1[,value2,...])
26         UPDATE table SET assignment1[,assignment2,...]
27         UPDATE table SET assignment1[,assignment2,...] WHERE condition
28
29

Operators available in conditions

31
32         "="  : equal
33         "<"  : smaller than
34         "<=" : smaller/equal than
35         ">"  : larger than
36         ">=" : larger/equal than
37         "<>" : not equal
38         "~"  : Substring matching
39
40
41        Arithmetic expressions using constants and field values are allowed in
42       condition  clauses  and  in  the  RHS of assignments.  Usual precedence
43       rules and bracketing (using '(' and ')') are supported.   Type  conver‐
44       sion is performed if necessary (experimental).
45
46        Aggregate  functions (sum, count, min, max,...) are NOT currently sup‐
47       ported in SELECT clauses.
48
49        Mathematic functions (sin, cos, exp, log,...) are NOT  currently  sup‐
50       ported in expressions.
51
52        Conditions  allow boolean expressions using the AND, OR and NOT opera‐
53       tors, with the usual precedence rules.
54
55        NULLs can be tested by 'colname IS NULL' in conditions.  The  negation
56       is 'colname NOT NULL'.
57

SEE ALSO

59       SQL support in GRASS GIS
60
61       Last changed: $Date: 2006/08/24 19:11:36 $
62       Help Index
63
64
65
66GRASS 6.2.2                                                       grass-dbf(1)
Impressum