Delete all tables in Derby DB

问题

How do i delete all the tables in the schema on Apache Derby DB using JDBC?

回答1:

For actual code that does this, check CleanDatabaseTestSetup.java in the Derby test suite section of the Derby distribution.

回答2:

Thanks are due to the blog:

Step 1:

Run the SQL statement, but don't forget to replace the schema name 'APP' with your your schema name in the 2 occurrences below:

SELECT
'ALTER TABLE '||S.SCHEMANAME||'.'||T.TABLENAME||' DROP CONSTRAINT '||C.CONSTRAINTNAME||';'
FROM
    SYS.SYSCONSTRAINTS C,
    SYS.SYSSCHEMAS S,
    SYS.SYSTABLES T
WHERE
    C.SCHEMAID = S.SCHEMAID
AND
    C.TABLEID = T.TABLEID
AND
S.SCHEMANAME = 'APP'
UNION
SELECT 'DROP TABLE ' || schemaname ||'.' || tablename || ';'
FROM SYS.SYSTABLES
INNER JOIN SYS.SYSSCHEMAS ON SYS.SYSTABLES.SCHEMAID = SYS.SYSSCHEMAS.SCHEMAID
where schemaname='APP';

Step 2:

The result of the above execution is a set of SQL statements, copy them to the SQL editor, execute them, then the constraints and the tables are dropped.

回答3:

Do a little method in java in which you execute a

DROP TABLE [tablename]

tablename is passed by parameter.

And another method in which you loop over a record set formed by the query

SELECT tablename FROM SYSTABLES

calling the first method.

Derby latest documentation

回答4:

I think most db providers don't allow DROP TABLE * (or similar).

I think the best way would be to SHOW TABLES and then go through each deleting in a loop via a resultset.

HTH.

回答5:

JDBC allows you to solve your task in a database agnostic way:

Open the connection
Grab the DatabaseMetaData
Use it to list all tables in your database JavaDoc
Iterate over the resultset and fire the DROP TABLE for each table

回答6:

you must generate schema and table name from Derby DB system catalog.
Order all tables by relation.
Generate java statement for drop all tables
Use autoCommit() method and set this method to false. for manual commit or rollback transactions when got errors.
Run you java process. Good Luck.

回答7:

A simpler solution is to use JDBC to run "drop database foo" then "create database foo". However, this will cause all objects in the DB to be deleted (i.e. not just tables).

回答8:

If you're working from the command prompt rather than through JDBC, this should get you started.

SELECT 'DROP TABLE ' || schemaname ||'.' || tablename || ';'
FROM SYS.SYSTABLES
INNER JOIN SYS.SYSSCHEMAS ON SYS.SYSTABLES.SCHEMAID = SYS.SYSSCHEMAS.SCHEMAID
;