constraints

I have a database which has a NOT NULL constraint on a field, and I want to remove this constraint. The complicating factor is that this constraint has a system-defined name, and that constraint's name differs between the production server, integration server, and the various developer databases. Our current process is to check in change scripts, and an automated task executes the appropriate queries through sqlplus against the target database, so I'd prefer a solution that could just be sent straight into sqlplus. On my own database, the SQL to drop this would be: alter table MYTABLE drop

I'd like to add a constraint which enforces uniqueness on a column only in a portion of a table. ALTER TABLE stop ADD CONSTRAINT myc UNIQUE (col_a) WHERE (col_b is null); The WHERE part above is wishful thinking. Any way of doing this? Or should I go back to the relational drawing board? PostgreSQL doesn't define a partial (ie conditional) UNIQUE constraint - however, you can create a partial unique index . PostgreSQL uses unique indexes to implement unique constraints, so the effect is the same, you just won't see the constaint listed in information_schema . CREATE UNIQUE INDEX stop_myc ON

I have an existing table called Persion . In this table I have 5 columns: persionId Pname PMid Pdescription Pamt When I created this table, I set PersionId and Pname as the primary key . I now want to include one more column in the primary key - PMID. How can I write an ALTER statement to do this? (I already have 1000 records in the table) drop constraint and recreate it alter table Persion drop CONSTRAINT <constraint_name> alter table Persion add primary key (persionId,Pname,PMID) edit: you can find the constraint name by using the query below: select OBJECT_NAME(OBJECT_ID) AS

How can I drop all user tables in oracle? I have problem with constraints. When I disable all it is still no possible. Henry Gao BEGIN FOR cur_rec IN (SELECT object_name, object_type FROM user_objects WHERE object_type IN ('TABLE', 'VIEW', 'MATERIALIZED VIEW', 'PACKAGE', 'PROCEDURE', 'FUNCTION', 'SEQUENCE', 'SYNONYM', 'PACKAGE BODY' )) LOOP BEGIN IF cur_rec.object_type = 'TABLE' THEN EXECUTE IMMEDIATE 'DROP ' || cur_rec.object_type || ' "' || cur_rec.object_name || '" CASCADE CONSTRAINTS'; ELSE EXECUTE IMMEDIATE 'DROP ' || cur_rec.object_type || ' "' || cur_rec.object_name || '"'; END IF;

I'm creating an SQL table that needs the fields from=date and to=date but I'd like to make a constraint so that to cannot be before from . My program will check for it but I'd like to learn how to enforce it with SQL. I've written SQL before but never really used constraints and don't know how they work. So the question is: Using standard SQL, how do I make sure that From is before To ? create table foo ( from_date date, to_date date, constraint check_dates check (from_date < to_date) ); Or if you need to apply this to an existing table, use: alter table foo add constraint check_dates check

I think this is a pretty common problem. I've got a table user(id INT ...) and a table photo(id BIGINT, owner INT) . owner is a reference on user(id) . I'd like to add a constraint to the table photo that would prevent more than let's say 10 photos to enter the database for each users. What's the best way of writing this? Thx! Quassnoi is right; a trigger would be the best way to achieve this. Here's the code: CREATE OR REPLACE FUNCTION enforce_photo_count() RETURNS trigger AS $$ DECLARE max_photo_count INTEGER := 10; photo_count INTEGER := 0; must_check BOOLEAN := false; BEGIN IF TG_OP =

While creating product, at the last step after retrieving for a time, Magento gives following error-: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1922-1' for key 'IDX_STOCK_PRODUCT' What I am doing is, by capturing product id, I am putting it's entry in custom table. I have connected to Magento database externally. Surprisingly data is inserted in both Magento's base table & also in Custom table but why it is giving me that error after product saving...? I cleared cache, browser cookies. Also remove /var/cache, /var/session. still giving error. Can anybody suggest a