Db2 cheat sheet for development
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This document provides a cheat sheet for Db2 development. It lists Db2 commands for executing SQL statements, defining and modifying database objects like tables and schemas, granting privileges, loading and exporting data, and writing SQL procedural language code. The cheat sheet covers topics like connecting to databases, creating and altering tables, writing queries, and committing transactions.
Db2 cheat sheet for development
- 1. Db2 Cheat Sheet for development Created by: Andres Gomez Casanova (@angoca) Version: 2019-02-02 Get the most recent version at https://github.com/angoca/db2-cheat-sheet/Db2CheatSheetForDev.pdf Execution of a file in the console (db2clp) ⢠Semi-colon separated sentences: db2 -t ⢠At sign separated sentences (when there is SQL PL code): db2 -td@ Define a terminator character --#SET TERMINATOR @ List all databases (aliases) LIST DB DIRECTORY Connect to a database (alias) CONNECT TO mydb Disconnect from a database CONNECT RESET TERMINATE Get values from the environment (registry values) ⢠Current timestamp VALUES CURRENT TIMESTAMP ⢠Connected user VALUES CURRENT USER ⢠Current database VALUES CURRENT SERVER List all tables LIST TABLES LIST TABLES FOR SCHEMA myuser LIST TABLES FOR ALL Change current schema SET CURRENT SCHEMA otherschema Change the isolation level (RR, RS, CS, UR) SET ISOLATION RR List all tablespaces with their status LIST TABLESPACES Describe the structure of the table DESCRIBE TABLE mytable Describe the result of a query DESCRIBE SELECT * FROM mytable Get help for a Db2 command ? command Get help for a SQL code (SQLXXXX) or SQLstate (YYYYY) ? SQLXXX ? YYYYY DDL Create a schema CREATE SCHEMA myschema Create a table in a specific tablespace CREATE TABLE mytable1 (mycol1 SMALLINT NOT NULL, mycol2 VARCHAR(16)) IN ts1 INDEX IN ts2 CREATE TABLE myschema.othertable (mycol1 SMALLINT) Create a table like another one CREATE TABLE mytable2 LIKE mytable1 IN ts1 INDEX IN ts2 Comment on table and column COMMENT ON TABLE mytable1 IS 'This is the comment of the table' COMMENT ON COLUMN mytable1.mycol1 IS 'Description of the field' Declare a temporary table DECLARE GLOBAL TEMPORARY TABLE mytemptab1 (col1 SMALLINT, col2 TIMESTAMP) Create a global temporary tablespace CREATE GLOBAL TEMPORARY TABLE tmptable (col1 INTEGER) Create an index CREATE UNIQUE INDEX myidx2 ON mytable1 (mycol2) Add a column (requires Reorg table) ALTER TABLE mytable1 ADD COLUMN mycol3 timestamp Change nullability ALTER TABLE mytable1 ALTER COLUMN mycol3 timestamp SET NOT NULL Rename a column ALTER TABLE mytable1 RENAME COLUMN mycol3 TO mynewcol3 Delete the identify of a column ALTER TABLE mytable1 TOODOOOOOOO Create a primary key constraint ALTER TABLE mytable1 ADD CONSTRAINT pkmytable PRIMARY KEY (mycol1) Drop primary key ALTER TABLE mytable1 DROP PRIMARY KEY Add identity ALTER TABLE mytable1 ALTER mycol1 SET GENERATED ALWAYS BY IDENTITY Drop identity ALTER TABLE mytable1 ALTER mycol1 DROP IDENTITY Create a foreign key ALTER TABLE mytable2 ADD CONSTRAINT fkmytable FOREIGN KEY (mycol1) REFERENCES mytable1 (mycol1) Create a check constraint ALTER TABLE mytable1 ADD CONSTRAINT chk CHECK (mycol2 in ('a', 'b', 'c')) Enforce a constraint ALTER TABLE mytable1 ALTER CHECK chk ENFORCED Not enforce a constraint ALTER TABLE mytable2 ALTER FOREIGN KEY fkmytable NOT ENFORCED Change the granularity of the locks ALTER TABLE mytable2 LOCKSIZE TABLE Drop a table DROP TABLE mytable Rename a table RENAME TABLE mytable2 AS myothertable Truncate a table TRUNCATE TABLE mytable1 IMMEDIATE Create a sequence CREATE SEQUENCE myseq AS INTEGER This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
- 2. Restart sequence ALTER SEQUENCE myseq RESTART WITH 15 Crete a stored procedure CREATE OR REPLACE PROCEDURE myproc (IN val SMALLINT, OUT ret VARCHAR(16)) SPECIFIC myproc1 BEGIN SET ret = (SELECT mycol2 FROM mytable1 WHERE mycol1 = val); END @ Create a trigger CREATE TRIGGER copy_value AFTER INSERT ON mytable1 REFERENCING NEW AS N FOR EACH ROW INSERT INTO mytable2 VALUES (N.mycol1, N.mycol2) Create a view CREATE VIEW VW1 AS SELECT mycol2 FROM mytable1 DCL Grant on a table GRANT SELECT, INSERT ON TABLE mytable TO GROUP recur Grant execution on a stored procedure GRANT EXECUTE ON PROCEDURE myproc(SMALLINT, VARCHAR(16)) TO USER jdoe GRANT EXECUTE ON SPECIFIC PROCEDURE myproc1 TO USER jdoe Revoke on a table REVOKE UPDATE, DELETE ON TABLE mytable FROM GROUP recur DML Insert values on a table INSERT INTO mytable1 VALUES (2, 'b') INSERT INTO mytable1 VALUES (3, 'c'), (4, 'd'), (5, 'e') --Atomic Insert certain columns INSERT INTO mytabl1 (mycol1) VALUES (6) Insert values from a select INSERT INTO myothertable SELECT mycol1, mycol2 FROM mytable1 Update fields UPDATE mytable1 SET mycol1 = 5, mycol2 = 'e' -âall table UPDATE mytable1 SET mycol2 = 'd' WHERE mycol1 = 7 Merge (upsert) MERGE INTO mytable1 AS t USING (SELECT mycol1 FROM myothertable) s ON (t.mycol1 = s.mycol1) WHEN MATCHED THEN UPDATE SET mycol2 = 'X' WHEN NOT MATCHED THEN INSERT VALUES (10, 'X') Delete rows DELETE FROM mytable1 -âall table DELETE FROM mytable1 WHERE mycol1 > 5 Export EXPORT TO myfile OF DEL SELECT * FROM mytable1 IMPORT FROM myfile OF DEL INSERT INTO mytable1 Cursor DECLARE mycursor CURSOR FOR SELECT * FROM mysrctable Load LOAD FROM myfile OF DEL INSERT INTO mytable1 LOAD FROM mycursor OF CURSOR INSERT INTO mytable1 Query the status of the load in a table LOAD QUERY TABLE mytable1 Set integrity SET INTEGRITY FOR mytable IMMEDIATE CHECKED Ingest INGEST FROM FILE my_file.txt FORMAT DELIMITED INSERT INTO my_table Get the next value from a sequence VALUES NEXT VALUE FOR myseq INSERT INTO mytabl1 (mycol1) VALUES (NEXT VALUE FOR myseq) TCL Commit changes COMMIT Create a savepoint SAVEPOINT sp1 ON ROLLBACK RETAIN CURSORS Undo changes until savepoint ROLLBACK TO SAVEPOINT sp1 Undo changes ROLLBACK Queries Put a lock at table level LOCK TABLE mytable1 IN EXCLUSIVE MODE Execute a query without regard of commit rows SELECT * FROM mytable WITH UR --RR,RS,CS Execute a query with only 5 rows SELECT * FROM mytable FETCH FIRST 5 ROWS ONLY Perform a query to a dummy table (dual) SELECT 'Any string' FROM SYSIBM.SYSDUMMY1 Perform a query calling a function SELECT HEX(mycol2) FROM mytable1 Call a function VALUES HEX('AnyText') Perform a cast VALUES CAST('123' AS INTEGER) Concatenate VALUES 'AnyText' || 5 VALUES 'AnyText' concat 5 Escape a single quote in a text field VALUES 'Sinead o''Connor' Query the database catalog SELECT * FROM SYSCAT.TABLES SELECT * FROM SYSCAT.TABAUTH SELECT * FROM SYSCAT.ROUTINES SQL PL Create a compound statement â Anonymous block BEGIN DECLARE val SMALLINT; SET val = 1; WHILE (val <= 5) DO INSERT INTO mytable VALUES (val, val); SET val = val + 1; END WHILE; END @ Perform a reorg via ADMIN_CMD (Sometimes required after âalter tableâ) CALL SYSPROC.ADMIN_CMD('REORG TABLE mytable') Call a stored procedure with an IN and an OUTPUT parameter CALL myproc(5, ?) This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.