Is it possible to easily see what tables exist in what schemas, at a glance?
So far I have had to connect to a database, view the schemas, then change the search path to one of the schemas and then list the tables. I had to do this for multiple schemas until I found the table I was looking for.
What if there is a scenario where you inherit a poorly documented database and you want to find a specific table in hundreds of schemas?
Ideally I imagine some output like so;
SCHEMA TABLE
--------------------
schema1 table1
schema2 table2
schema2 table1
--------------------
Or even the more standard <SCHEMA_NAME>.<TABLE_NAME>;
schema1.table1
schema2.table2
schema2.table1
The latter output would be even better since you could simply check the table using copy-paste;
my-database=# \d schema2.table1
Ideally I'm hoping I missed a built-in command to find this. I don't really want to create and memorize a lengthy SQL command to get this (somewhat basic) information.
You can make use of pg_tables
SELECT schemaname, tablename,
quote_ident(schemaname) || '.' || quote_ident(tablename)
FROM pg_tables
WHERE tablename = 'test';
Related
question is pretty simple, but can't seem to find a concrete answer anywhere.
I need to update all tables inside my postgresql schema to include a timestamp column with default NOW(). I'm wondering how I can do this via a query instead of having to go to each individual table. There are several hundred tables in the schema and they all just need to have the one column added with the default value.
Any help would be greatly appreciated!
The easy way with psql, run a query to generate the commands, save and run the results
-- Turn off headers:
\t
-- Use SQL to build SQL:
SELECT 'ALTER TABLE public.' || table_name || ' add fecha timestamp not null default now();'
FROM information_schema.tables
WHERE table_type = 'BASE TABLE' AND table_schema='public';
-- If the output looks good, write it to a file and run it:
\g out.tmp
\i out.tmp
-- or if you don't want the temporal file, use gexec to run it:
\gexec
Is there a way to find all table names that begin with t_ in a given schema name with criteria API or query DSL( or even database metadata)? If it exists, could you please show me how I can do it using a schema name or view? I'm using PostgreSQL for the database.
I don't want to use a native query.
yes, you can use below query:
SELECT table_catalog,table_schema,table_name
FROM information_schema.tables
WHERE table_name LIKE 't\_%'
AND table_type='BASE TABLE' -- to filter out Tables only, remove if you need to see views as well
I am just learning the CTE and I want to create the dynamic query inside the WITH clause.
Below is what i have written code.
WITH name1 AS (
SELECT schema_name as my_schema
FROM public.schema_table
), name2 AS (
SELECT num_rows as my_row
FROM my_schema.row_table
)
SELECT my_row
from name2;
From the first query inside the WITH give number of schema exist in one database and that schema name return by
SELECT schema_name as my_schema
FROM public.schema_table
I want to use in second query as I am saving it to my_schema.
but when i run this query then it gives me error like my_schema not exists that correct because I want to use the value my_schema contains.
How can you do that?
Firstly, you do not appear to have used name1 anywhere in your query, so I suspect you may not have understood WITH fully.
However it looks like you might have multiple tables called row_table each living in it's own schema and want to create a query that will let you choose which schema to fetch from.
FROM my_schema.row_table
^^^^^^^^^
my_schema is not a variable, it is the name of the schema. To do what you want you are going to have to use the pg_catalog tables to find the oid for the relation within the schema that you need and look up the information that way.
An alternative solution could be to manipulate the search path to do your bidding:
BEGIN;
SET LOCAL SCHEMA 'my_schema';
SELECT num_rows FROM row_table; -- will use my_schema.
COMMIT;
How do I drop all tables whose name start with, say, doors_? Can I do some sort of regex using the drop table command?
I prefer not writing a custom script but all solutions are welcomed. Thanks!
This script will generate the DDL commands to drop them all:
SELECT 'DROP TABLE ' || t.oid::regclass || ';'
FROM pg_class t
-- JOIN pg_namespace n ON n.oid = t.relnamespace -- to select by schema
WHERE t.relkind = 'r'
AND t.relname ~~ E'doors\_%' -- enter search term for table here
-- AND n.nspname ~~ '%myschema%' -- optionally select by schema(s), too
ORDER BY 1;
The cast t.oid::regclass makes the syntax work for mixed case identifiers, reserved words or special characters in table names, too. It also prevents SQL injection and prepends the schema name where necessary. More about object identifier types in the manual.
About the schema search path.
You could automate the dropping, too, but it's unwise not to check what you actually delete before you do.
You could append CASCADE to every statement to DROP depending objects (views and referencing foreign keys). But, again, that's unwise unless you know very well what you are doing. Foreign key constraints are no big loss, but this will also drop all dependent views entirely. Without CASCADE you get error messages informing you which objects prevent you from dropping the table. And you can then deal with it.
I normally use one query to generate the DDL commands for me based on some of the metadata tables and then run those commands manually. For example:
SELECT 'DROP TABLE ' || tablename || ';' FROM pg_tables
WHERE tablename LIKE 'prefix%' AND schemaname = 'public';
This will return a bunch of DROP TABLE xxx; queries, which I simply copy&paste to the console. While you could add some code to execute them automatically, I prefer to run them on my own.
I have a problem where I need to remove all code and triggers from a database that relate to certain tables in order for a Solaris package to install. Long complicated story but I need
to start with a clean slate.
I've managed to remove all the existing tables/synonyms, but how to locate the code/triggers from sqlplus that is related?
Unfortunately, it's not feasible to drop the database and recreate it.
Well, it turns out all the table names are prefixed with my module name DAP.
So, to find all the table names and public synonyms with sqlplus:
select table_name from all_tables where table_name like 'DAP%';
select synonym_name from all_synonyms where table_name like 'DAP%';
To get a list of triggers and sequences
select trigger_name from all_triggers where table_name like 'DAP%';
select sequence_name from all_sequences where sequence_name like 'DAP%';
To get a list of all the constraints
select table_name, constraint_name from all_constraints where table_name like 'DAP%';
To get the DAP related code:
select text from dba_source where name like 'DAP%';
I can now write a script that drops everything.
You should be able to query the system table ALL_TRIGGERS to find the triggers. It has a table_name column. You can probably find the other related objects with different system tables (been awhile since I've messed with Oracle).
http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/statviews_2107.htm