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grass-dbf.1grass
Langue: en
Version: 313065 (ubuntu - 07/07/09)
Section: 1 (Commandes utilisateur)
Sommaire
Creating a DBF table
Usually DBF tables are created by GRASS when generating a vector map with attribute (and using DBF as default attribute driver).If a DBF table has to be created manually, db.execute can be used or a spreadsheet application. Also db.copy is sometimes useful.
Supported SQL commands by DBF driver
ALTER TABLE table ADD [COLUMN] columndef
CREATE TABLE table ( columndefs )
DROP TABLE table
SELECT columns FROM table
SELECT columns FROM table WHERE condition
DELETE FROM table
DELETE FROM table WHERE condition
INSERT INTO table VALUES (value1[,value2,...])
INSERT INTO table ( column1[,column2,...] ) VALUES (value1[,value2,...])
UPDATE table SET assignment1[,assignment2,...]
UPDATE table SET assignment1[,assignment2,...] WHERE condition
Operators available in conditions
"=" : equal
"<" : smaller than
"<=" : smaller/equal than
">" : larger than
">=" : larger/equal than
"<>" : not equal
"~" : Substring matching
Arithmetic expressions using constants and field values are allowed in condition clauses and in the RHS of assignments. Usual precedence rules and bracketing (using '(' and ')') are supported. Type conversion is performed if necessary (experimental).
Aggregate functions (sum, count, min, max,...) are NOT currently supported in SELECT clauses.
Mathematic functions (sin, cos, exp, log,...) are NOT currently supported in expressions.
Conditions allow boolean expressions using the AND, OR and NOT operators, with the usual precedence rules.
NULLs can be tested by 'colname IS NULL' in conditions. The negation is 'colname NOT NULL'.
SEE ALSO
SQL support in GRASS GISLast changed: $Date: 2006/08/24 19:11:36 $
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