lunes, 10 de marzo de 2014

DB2 - Consultas de metadatos - Consultas recursivas



DB2 – consulta de metadatos

Catalog Schema: Doc original / standard name: syscat à DB2 alias: ibm

triggers
select text from sysibm.sysTRIGGERS where tbname

secuencias
select * from sysibm.syssequences where owner

stored procedure / function
select * from SYSIBM.sysroutines where owner

PK, unique constraint, FK,
select * from SYSIBM.syskeycoluse where constname
select * from SYSIBM.SYSRELS where RELNAME
select * from SYSIBM.SYSFOREIGNKEYS where relname

tables
FROM SYSIBM.SYSTABLES 
FROM SYSIBM.SYSCOLUMNS where tbname and tbcreator

Dummy
sysibm.sysdummy1

Consultas recursivas en DB2 (jerarquía jerárquicas hierarchy hierarchial recursive)

/************************************************************************/
/************************************************************************/
/******************* COMPARE THE FOLLOWING 2 QUERIES  *******************/
/************************************************************************/
/************************************************************************/
-- TOP-DOWN
with MY_HIERARCHY (MY_NODE, MY_PARENTNODE) as (
      -- non-recursive exit
      select ROOT.MY_NODE, ROOT.MY_PARENTNODE
      from THETABLE ROOT where MY_NODE='value'   -- the root node in the tree

      union all
      -- recursive loop (it needs the non-recursive part in order not to be an empty set)
      select CHILD.MY_NODE, CHILD.MY_PARENTNODE
      from MY_HIERARCHY PARENT, THETABLE CHILD
      where CHILD.MY_PARENTNODE = PARENT.MY_NODE   -- top-down join

)
select * from MY_HIERARCHY


-- BOTTOM-UP
with MY_HIERARCHY (MY_NODE, MY_PARENTNODE) as (
      -- non-recursive exit
      select LEAF.MY_NODE, LEAF.MY_PARENTNODE
      from THETABLE LEAF where MY_NODE='value'   -- the leaf node in the tree

      union all
      -- recursive loop (it needs the non-recursive part in order not to be an empty set)
      select CHILD.MY_NODE, CHILD.MY_PARENTNODE
      from MY_HIERARCHY PARENT, THETABLE CHILD
      where CHILD.MY_NODE = PARENT.MY_PARENTNODE   -- bottom-up join

)
select * from MY_HIERARCHY

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