A declarative mechanism such as a check or foreign key that enforces some data integrity rule in a database.

learn more… | top users | synonyms

0
votes
1answer
8 views

Field Prerequisite on Another

I would like to know if it's possible to have two fields (in this case bits) in the same table where one is prerequisite on another. For example Check2 may only be true if Check1 is true. Note: I'm ...
0
votes
2answers
75 views

check key if exists in other table without fk constraint

Lets say i have: table a (id_a int); table b (id_b int, id_a int); I want to check if b.id_a exists in "a" before a new row in "b" will be inserted. Normally I would just add a fk constraint on ...
0
votes
0answers
24 views

Cannot drop constraint in SQL server 2008

When I try to delete a constraint, it gives me the following message: "The constraint is used by merge replication for identity management and cannot be dropped directly. Execute ...
0
votes
0answers
25 views

Email Column Constraint to Contain '@' character

How do you create an inline constraint for a Email Address Field that requires there be an "@" character? Pretty much I want there to be a restriction to the field so that the data entered must have ...
2
votes
1answer
32 views

How to enforce an “exactly-one-per-group” constraint?

I have a table x that I've defined like this: CREATE TABLE x ( xid INTEGER NOT NULL PRIMARY KEY, yid INTEGER NOT NULL REFERENCES y(yid), is_principal BOOLEAN NOT NULL ); This definition ...
0
votes
0answers
31 views

Can I create a constraint to a subset of data? [duplicate]

Here's a simplified view of my database |---------------| |-----------| | ORGANIZATION | | CONTACT | |---------------| |-----------| | OrgId | | ContactId | | OrgName ...
-1
votes
2answers
52 views

What happens when play with constraints [closed]

I'm inserting data from one DB to one other on another instance by using the following method: Create insert into scripts from the source DB. TargetDB: DROP constraints, insert data and Create ...
1
vote
1answer
70 views

Performance of single vs multiple column unique constraint

I'm using PostgreSQL 9.3. I want to understand if I have an option to make a constraint unique across the entire table vs. unique across a subset of the table (i.e. by using 2 columns in the unique ...
1
vote
1answer
97 views

MySQL unique index only if column has specific value

I have a table where I use a boolean column deleted to signify whether a specific record has been 'deleted' by the user (meaning, it appears in the trash list instead of the normal list). These items ...
1
vote
1answer
49 views

Change constraint on column based on value of another

Is it possible to change a constraint on a column in postgres based on the value of another column? E.g. (pseudocode): CREATE TABLE transactions( id SERIAL PRIMARY KEY, type TXN_TYPE NOT ...
0
votes
1answer
38 views

Oracle Missing Comma error on check constraint

I'm attempting to create a table in Oracle, but keep getting the "ORA-00917":missing comma error at the end of my first constraint (P_IMAGEFILE_CHECK). I've tried adding and taking away commas but ...
0
votes
1answer
30 views

Constrain Partial Values in Timestamp

I'm working on a some Create Table statements for a project I have. I have two columns (StartDate, EndDate) where the data type is Timestamp. One of the requirements is to ensure that the date is ...
0
votes
2answers
81 views

How to I establish a 1 to 1 relationship

I have a table Nurse: CREATE TABLE [dbo].[Nurse]( [EmployeeId] [int] IDENTITY(1,1) NOT NULL, [WardId] [int] NOT NULL, CONSTRAINT [PK_Nurse] PRIMARY KEY CLUSTERED ( [EmployeeId] ASC ...
0
votes
0answers
36 views

How to combine a default value with a new value?

I need to start the value of a column with CON, so when I insert a new value, it needs to "combine" both default and new value; for example: In the CONTACTO_ASP2_TAB table, the column NOMBRE has to ...
2
votes
1answer
87 views

Why does MySQL increment the auto_increment value when there's a constraint violation?

I have a table in a MySQL database with one column id, which has auto_increment and the Primary Key. There's also a Unique constraint in this table, on different columns. I noticed that when I try to ...
0
votes
1answer
52 views

I see a constraint in my table thats not in INFORMATION SCHEMA?

When I expand the database "Constraints" object, I see 2 of them named DF_DocumentD_Docum_3F466844 and df_documentdistqty, but when I select to view everything from the "Information Schema.TABLE ...
2
votes
1answer
31 views

Is it possible to enforce a Unique Constraint on a Dataset comprised of joins

I am playing around with an idea to describe friendships in a system, and I am wondering about constraints. I currently have a database that looks like this: Users: ...
1
vote
1answer
182 views

Adding foreign keys constraint on databases used

We have a server with about 20 databases, all duplicates of the same original db, and we just noticed the original is missing all the foreign keys constraint for some unknown reason. So of course all ...
2
votes
3answers
231 views

Constrain a postgres timestamp to “End of day”?

Given a table named bananas and a timestamp without time zone column named end_time and some psql clients have set timezone to 'UTC' and other psql clients have set timezone to 'US/Eastern' and the ...
5
votes
2answers
58 views

How to enforce the structural constraints of rectangularly arrayed data?

(I'm particularly interested in answers that view the question below as a special case of the question: how should a RDBMS enforce structural constraints that are more specific than "one-to-many" and ...
2
votes
2answers
174 views

Adding standard set of constraints (rules) to PostGIS `raster` type column

Following on from my related prior question, let me elaborate this topic a bit. raster2pgsql is a raster loader executable that loads GDAL supported raster formats in PostGIS. It has a -C flag ...
1
vote
2answers
153 views

Creating a unique constraint on a PostGIS 'raster' type column

I am using the following command to add constraints to one of the raster image in PostGIS-2.1.3 (PostgreSQL-9.1.14). ALTER TABLE schema1.table1 ADD CONSTRAINT enforce_scalex_rast unique (rast); But ...
0
votes
0answers
119 views

cascade delete doesn't work even though constraint is added

I created the following table: CREATE TABLE message_link ( id serial NOT NULL, thread_id integer, message_id integer, user_id integer, read boolean NOT NULL, CONSTRAINT message_link_pkey ...
1
vote
1answer
27 views

How to put this particular constraint on this link table in MySQL? [duplicate]

I have the following three tables in MySQL: Store, Groups, StoreGroup. A store can belong to several groups. StoreGroup is the link table that records the groups a store belongs to. The Groups table ...
1
vote
1answer
86 views

Restrict two specific column values from existing at the same time

I have a PostgreSQL example table where at most one row that is not of type 'c' should be allowed. I would appreciate any help creating a constraint that will enforce this. CREATE TABLE example ( ...
9
votes
2answers
3k views

foreign key constraint violation issue

I have identified 3 situations. A student with no enrollments. A student with enrollments but no grades. A student with enrollments and grades. There is a trigger on the enrollments table to ...
0
votes
0answers
88 views

SQL Server - constraint to prevent overlapping dates [duplicate]

I saw this wonderful article called "CHECK Constraint To Avoid Overlapping Data" It basically boils down to this: CREATE TABLE Reservations (ReservationID int NOT NULL PRIMARY KEY, ...
1
vote
0answers
32 views

Clarify unique constraint and index, cannot grasp the concepts to 100% [duplicate]

When reading about UNIQUE, I understand the concept but when it comes to the practical part of it, I get confused and I'm unsure of what it means. What I do understand, is that there are two ways to ...
0
votes
1answer
40 views

PostgreSQL: How does the implicit index work when using “COPY” for loading bulk rows into a newly created table?

What I know for fast loading bulk rows into a new table is: Create the table(without creating the index) Use "COPY" to load data from a file into the table Create the index What if I added a ...
0
votes
1answer
71 views

SQL Server - Is it possible to forbid creation of default constraint name?

I was having a looking on this article about default constraints and I have a question. Is there a configuration in SQL Server 2008 that forbid naming creation of new default constraints declared ...
0
votes
2answers
319 views

Msg 2627 Violation of PRIMARY KEY constraint

trying to make a database for teams in a tv show here. but when I try and insert data into tblShowteam the following error made its appearance. Msg 2627, Level 14, State 1, Line 2 Violation of ...
0
votes
1answer
1k views

Cannot add foreign key constraint while creating table

My Error Code is 1215 which finds problem with the foreign key constraint. I know all fields are the same data types. I can't see where the problem is. Any help would be much appreciated! Thanks! ...
1
vote
1answer
1k views

How to insert data into tables which reference each other?(MySQL)

I'm a student and right now I have a problem that I couldn't solve by myself(after searching on the Internet). I'm not going to give my «homework» because I want to learn what I'm doing but I will ...
1
vote
1answer
115 views

How to force MySQL Workbench to use constraints in my file?

I'm currently working on a project that requires I write my own constraints for my database (to show I know how they work). I'm attempting to test them in MySQL Workbench however the programs settings ...
0
votes
2answers
156 views

SQL Check Constraint that requires a not null value in a column based on the value of another column

I have a table with the following two columns OnSite BIT NOT NULL ClientId INT NULL I want to add a constraint that requires ClientId to be NOT NULL when OnSite is true(1). I could not find ...
0
votes
2answers
789 views

Primary key within JSON data in Postgresql

I have a table t, with a column called json, of type JSON. Within the JSON there is a natural key: > SELECT json->'id' AS id FROM t LIMIT 1; id ...
1
vote
1answer
153 views

Alternatives to NULL for missing data [duplicate]

I am using PostgreSQL and trying to write value constraints. Is it possible to record missing data as distinct from NULL values in a numeric field without using an arbitrary numeric value? For many ...
3
votes
1answer
94 views

constraint in oracle

I'm trying modeling things like this using oracle: An account can have 1~5 members So I'll have a account table and a member table with a FK of account. But is that possible to check if the account ...
0
votes
1answer
29 views

Require uniqueness with group by

I'm not sure how to couch this question. I have a table that has multiple columns including an id column, a foreign key column 'JobId', and a 'GxpId' column. I have a requirement that a 'JobId' can ...
2
votes
3answers
1k views

Listing indexes and constraints

I am looking at a SQL Server database for an application I have inherited. I have not looked into SQL Server for approximately 10 years, so please bear with me. The database table I am looking at has ...
1
vote
1answer
253 views

How do I validate all my constraints in postgresql?

It seems like I have been bitten by the first bug described in the release notes of postgresql 9.3.4: http://www.postgresql.org/docs/devel/static/release-9-3-4.html I now have e.g. duplicate primary ...
0
votes
1answer
560 views

What is the difference between covering and overlapping constraints use in DBMS?

What is the difference between covering and overlapping constraints use in DBMS?
2
votes
1answer
79 views

Confused on how a value gets added with the DEFAULT constraint

A recent definition I've read about Default Constraints: DEFAULT is specified for a column to assign a column a specific value if no value is specified when a row is added. I believe I've seen code ...
2
votes
1answer
39 views

How can I model and enforce constraints on a categorical item contained in a collection?

Scenario: There is a collection of items where each item belongs to 1 category. There is a collection of buckets which may contain at most 1 item from each category. Oh, and an item may belong to at ...
2
votes
1answer
168 views

Two relations to same table in SQL Server

I've got two tables. When I delete a row in Table1, I want to set the ID of that row in all the rows of Table2 to NULL. I've got two relationships on Table1. The problem is: I can only set one delete ...
0
votes
0answers
51 views

Two different unique constraints for 1 table?

I must enforce uniqueness within my table, But I cannot seem to find anywhere online(mysql manual,forums,stack overflow) talk about two unique constraints within one table. Why you might ask I need ...
0
votes
1answer
32 views

design DB review and check constraint for postalcode help?

Hi. I created this database to just to sharpen my skill. I have one Question - when I create I make the FOREIGN KEY personID in Addresses table but I changed it to be AddressID in Persons table ...
1
vote
0answers
803 views

User defined table type with a check constraint

I have a user defined table type where I want to make sure that a certain column is within a given range. This range however is defined in another table. So I thought I can use a check constraint on ...
0
votes
1answer
80 views

Is it possible to have a unique key condition based on another value?

I have a table with the following columns: ID, STRING_VALUE, ENUM_VALUE, CATEGORY_IDENTIFIER I'd like to create a condition that won't allow two identical ENUM_VALUEs, but only if their ID is also ...
2
votes
0answers
170 views

Postgres 9.3 - deletes terribly slow for 10 minutes after dropping indexes/constraints

If I run a script which drops indexes (17 of them, CONCURRENTLY makes no difference except that without it I get the occasional deadlock), then constraints (20 constraints on 18 tables) and then run a ...