Datenbanksysteme: Unterschied zwischen den Versionen
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Omega (Diskussion | Beiträge) K (→Zusammenhänge) |
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Zeile 95: | Zeile 95: | ||
<math>\pi_{Vorname, Name}(\sigma_{Ort='Berlin'}(Kunden))</math> | <math>\pi_{Vorname, Name}(\sigma_{Ort='Berlin'}(Kunden))</math> | ||
<pre> | <pre> | ||
− | + | SELECT Vorname, Name | |
FROM Kunde | FROM Kunde | ||
WHERE Ort = ’Berlin’ | WHERE Ort = ’Berlin’ | ||
</pre> | </pre> |
Version vom 8. Februar 2006, 15:28 Uhr
Relationale Datenbanken
Relationenalgebra
Selection
Projektion
SQL-Formulierung
CREATE TABLE
CREATE TABLE tbl_name ( [ col_name type [NOT NULL | NULL] [DEFAULT default_value] [AUTO_INCREMENT] [ UNIQUE [KEY] | [PRIMARY] KEY] | PRIMARY KEY [index_type] (index_col_name,...) | FOREIGN KEY (index_col_name,...) [REFERENCES tbl_name [(index_col_name,...)]] ],... );
SELECT
SELECT [DISTINCT] select_expr, ... [FROM table_references [WHERE where_condition] [GROUP BY {col_name | expr | position} [ASC | DESC], ... [WITH ROLLUP]] [HAVING where_condition] [ORDER BY {col_name | expr | position} [ASC | DESC], ...]
Verschachtelung mit where_condition möglich.
WHERE [NOT] IN references
INSERT
INSERT INTO tbl_name [(col_name,...)] VALUES ({expr | DEFAULT},...),(...),...
UPDATE
UPDATE table_references SET col_name1=expr1 [, col_name2=expr2 ...] [WHERE where_condition]
DELETE
DELETE FROM tbl_name [WHERE where_condition]
Zusammenhänge
SELECT Vorname, Name FROM Kunde WHERE Ort = ’Berlin’