DB2 System Commands
DB2ILIST -- lists all instances installed
DB2CMD -- opens a command line processor
DB2CC -- opens db2 control center
DB2LICM -l -- gets db2 type.
Command Line Processor Commands
Database commands via Command Line Processor (CLP)
DB2 LIST NODE DIRECTORY -- Lists all nodesDB2 CATALOG TCPIP NODE DB2NODE REMOTE servername SERVER 50000 -- catalogs node. In this case, node is db2Node on the machine with name servername. Port is 50000.
DB2 LIST DATABASE DIRECTORY -- list databases
DB2 GET DB CFG FOR SAMPLE -- get configuration info for the SAMPLE db.
DB2 CONNECT TO dbname USER myuser USING mypass -- connect to db. In this case, database is dbname, usern is myuser and password is mypass.
DB2 DISCONNECT dbname -- disconnects
DB2 LIST APPLICATIONS SHOW DETAIL -- shows all running db's
DB2 GET DBM CFG -- view authentication paramater (e.g. something like server_encrypt)
DB2 UPDATE DBM CFG USING AUTHENTICATION SERVER_ENCRYPT -- alter the authentication mechanism to server_encrypt
DB2 GET AUTHORIZATIONS -- get authorisation level.
DB2 GET DATABASE CONFIGURATION -- gets current database configuration
DB2 VALUES CURRENT USER - - gets the current user
DB2 VALUES CURRENT SCHEMA -- gets the current schema
DB2 VALUES CURRENT QUERY OPTIMIZATION -- get query optimization level.
Schemas
DB2 SELECT SCHEMANAME FROM SYSCAT.SCHEMATA -- list all schemas
DB2 VALUES CURRENT SCHEMA -- gets the current schema
DB2 SET SCHEMA ALEXSCHEMA -- set schema
Tables
DB2 LIST TABLES FOR schema_name -- list all tables for particular schema
DB2 LIST TABLES SHOW DETAIL; -- show detail about tables
DECLARE GLOBAL TEMPORARY TABLE -- declares a temporary table
CREATE TABLE MQT AS (SELECT c.cust_name, c.cust_id, a.balance FROM customer c, account a WHERE c._cust_name IN ('Alex') AND a.customer_id - c.cust_id) DATA INITIALLY DEFERRED REFRESH DEFERRED -- Creates a materialised query table. In this case the MQT is based on a join query from the customer and account table.
Tablespaces
SELECT * FROM SYSCAT.TABLESPACES; -- show what syscat has about tablespaces
SELECT tbspace, bufferpoolid from syscat.tablespaces; -- get tablespace and bufferpoolid
SELECT TABNAME FROM SYSCAT.TABLES WHERE TBSPACE=2; -- Check what TABLES are in tablespace where id = 2.
Constraints
SELECT * FROM SYSCAT.CHECKS; -- Colum checks
SELECT * FROM SYSCAT.COLCHECKS; -- Column constraints
SELECT * FROM SYSCAT.REFERENCES; -- Referential constraints
Sequences
CREATE SEQUENCE STESTRESULT AS INTEGER INCREMENT BY 1 START WITH 1 NO MINVALUE NO MAXVALUE NO CYCLE CACHE 10 ORDER; -- Create Sequence starting with 1 which cache 10 values
SELECT * FROM SYSCAT.SEQUENCES; -- Gets systcat info on sequences
VALUES NEXT VALUE FOR MYSEQ; -- Gets next value from sequence myseq
ALTER SEQUENCE MYSEQ RESTART WITH 11 INCREMENT BY 1 MAXVALUE 10000 CYCLE CACHE 12 ORDER -- Changes MySeq sequence
Locksize
SELECT TABNAME, LOCKSIZE FROM SYSCAT.TABLES WHERE TABNAME = ' EMPLOYEES'; -- Check locksize which can be tablespace, table, partition, page, row - (usually row).Bufferpools
SELECT buffer.bufferpoolid, buffer.bpname, buffer.npages, buffer.pagesize, tablespace.tbspace, tablespace.tbspaceid from syscat.bufferpools buffer, syscat.tablespaces tablespace where tablespace.bufferpoolid = buffer.bufferpoolid; -- gets buffer pool and corresponding tablespace info.
Indexes
SELECT COLNAMES, TABNAME, INDEXTYPE, CLUSTERRATIO, CLUSTERFACTOR FROM SYSCAT.INDEXES WHERE TABNAME = 'TPERSON'; -- some useful columns
Functions
SYSDUMMY1 commands
Runstats
SELECT CURRENT DATE FROM SYSIBM.SYSDUMMY1; -- gets current date.SELECT HEX(36) FROM SYSIBM.SYSDUMMY1; -- same as VALUES HEX(36)
SELECT XMLCOMMENT ('This is an XML comment') FROM SYSIBM.SYSDUMMY1;
RUNSTATS ON TABLE TAUSER1.TOSUSER FOR INDEXES ALL; -- runstats for all indexes
Checking the last time runstats was run...
SELECT CARD, STATS_TIME FROM SYSCAT.TABLES WHERE TABNAME = 'TOSUSER';
SELECT NLEAF, NLEVELS, FULLKEYCARD, STATS_TIME, TABNAME, INDNAME FROM SYSCAT.INDEXES WHERE TABNAME = 'TOSUSER';
The following catalog columns can be queried to determine if RUNSTATS has been performed on the tables and indexes:
If the CARD column of the SYSCAT.TABLES view displays a value of -1, or the STATS_TIME column displays a NULL value for a table, then the RUNSTATS utility has not run for that table.
If the NLEAF, NLEVELS and FULLKEYCARD columns of the SYSCAT.INDEXES view display a value of -1, or the STATS_TIME column displays a NULL value for an index, then the RUNSTATS utility has not run for that index.
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