How to get constraint definition in postgresql. The user who defines a domain becomes its owner.

If the FK references a primary key, no columns are needed. To enforce the listed combinations, your table definition could look like this: CREATE TABLE jobs. If a schema name is given (for example, CREATE DOMAIN myschema. from information_schema. a integer, b integer, UNIQUE (a, b) ); But using ALTER TABLE to add a constraint it seems a name is mandatory: ALTER TABLE example ADD CONSTRAINT my_explicit_constraint_name UNIQUE (a, b); This has caused some naming Oct 1, 2021 · 3. Introduction to PostgreSQL CHECK constraints. To remove data from the main table and all tables that have foreign key references to the main table, you use CASCADE option as follows: TRUNCATE TABLE table_name CASCADE; A not-null constraint is always written as a column constraint. rel - relationship symbol implicating direction. 20-1. WHERE table_name = 'your_table'. You need to retrieve the table names by running the following query: SELECT *. Every column constraint is equivalent to some table constraint. A uniqueness restriction covering only some rows cannot be written as a unique constraint, but it is possible to enforce such a restriction by creating a unique partial index. Constraints are an essential part of the relational model, as they define rules that the data within the database must follow. Name of the database that contains the constraint (always the current Users can also define their own data types. answered Feb 12, 2015 at 15:27. Click on the Save button to add the unique constraint on the selected columns. That means the record is not OK otherwise (if it does not contain 'A'). 64. In PostgreSQL, a CHECK constraint ensures that values in a column or a group of columns meet a specific condition. drop_all() methods do this by default, using a topological sort of all the Table objects involved such that tables are created and dropped in order of their foreign key dependency (this sort is also available via the Aug 8, 2014 · When creating a table in PostgreSQL, default constraint names will assigned if not provided: CREATE TABLE example (. module. FROM pg_constraint. If the FK references an alternate key, columns are needed. routines WHERE routine_type='FUNCTION' AND specific_schema='public' AND routine_name = 'my_func' That returns in my case: Jun 9, 2009 · ALTER TABLE name RENAME CONSTRAINT constraint_name TO new_constraint_name; It turned out that our existing contraints began with "FK_", i. ) In PostgreSQL, a foreign key is a column or a group of columns in a table that uniquely identifies a row in another table. The table containing a foreign key is referred to as the referencing table or . Dec 26, 2023 · To add a constraint if it does not already exist, you can use the following syntax: sql. 6. table_name , ctu. Simpler, cheaper and more reliable than a trigger. 8. Start by creating a project directory for the files that you'll create throughout this guide. columns 6 WHERE 7 table_name = '<table_name>'; Replace with the name of the table you want to describe. Add Unique Constraint Definition. In above statement, mytable is the name of the table you want to modify, column_name is the name of the column you want to make unique, and unique_column_name is a name you choose for the unique Description. Dec 16, 2012 · SELECT tc. The value of the column c2 or c3 needs not to be unique. 04+1), compiled by gcc (Ubuntu 7. 20 on x86_64-pc-linux-gnu (Ubuntu 9. exports = (sequelize, DataTypes To make a column unique in a PostgreSQL table, you can use the ALTER TABLE statement with the ADD CONSTRAINT clause. Open terminal or command line and run the following commands: mkdir check-demo. Jul 27, 2011 · That is something like (for single column constaint): tableName_columnName_key. UNIQUE (email); Note that if there are existing duplicates in the column, PostgreSQL won’t let you add the constraint until those duplicates are resolved. Let’s run the query on the employee table: Running the query in DbVisualizer. Alternatively you can use pg_constraint to retrieve this information. If there is no match, the result is NULL. Index Access Method Interface Definition. column_name, pgc. ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5); Now, if I want to drop that constraint with ALTER DOMAIN, The manual says: ALTER DOMAIN name. ALTER VIEW changes various auxiliary properties of a view. ) Advanced Features. constraint_catalog sql_identifier. You mention that you have 'separate unique constraints on col1 and col2', so I might assume your table definition is similar to this: Jun 1, 2020 · PostgreSQL provides the user with a UNIQUE constrain that is used to make sure that values stored in a column or a group of columns are unique across rows in a table. pg_get_constraintdef() was added in PostgreSQL 7. However the FK column should not be defined as serial it should defined as integer. To disable foreign keys and deferrable unique and primary key constraints for a table, you can use. This is what I tried : SELECT constraint_name, constraint_type. To add the NOT NULL constraint to a column of an existing table, you use the following form of the ALTER TABLE statement: ALTER COLUMN column_name SET NOT NULL; Code language: SQL (Structured Query Language) (sql) To add multiple NOT NULL constraints to multiple columns, you use the following syntax: Jan 30, 2023 · 1. contype = 'f') then ccu. Most built-in data types have obvious names and semantics, so we defer a detailed explanation to Chapter 8 . Jul 20, 2009 · JOIN information_schema. Nov 9, 2019 · The constraints are implemented as internal triggers in postgres and you can disable all the triggers for a table, run the statements you'd like to run without constraints and then re-enable the constraints. table_schema as table_schema, kcu. If you feel the need to do this for a column which is not a foreign key, it means that Jun 27, 2024 · If an exclusion constraint, list of the per-column exclusion operators. Index Uniqueness Checks #. CREATE DOMAIN creates a new domain. I have created the required tables. or use pg_constraint system catalog: SELECT conname. Next, make sure that your PostgreSQL database server is running. regexp_like('Hello World', 'world', 'i') true. constraint_table_usage ctu on ctu. Something like the following may work for you. Oct 1, 2015 · e. primary_table - primary (rerefenced) table schema and name. pronamespace WHERE n. This is called maintaining the referential integrity of your data. The Schema. column_name end as column_name, case when (pgc. Now, go to the Definition tab and select one or more columns where you want to apply the unique constraint, as shown below. The drawback is that you cannot give explicit names to not-null constraints created this way. Schemas are in pg_namespace. Unique Indexes #. Jan 17, 2022 · 184. When an index is declared unique, multiple May 28, 2015 · Part 2: Query the definition of a materialized view: In order to come up with a query to get the definition of the mat view, I first had to look up the definition of the information_schema. conname as constraint_name, ccu. 50. In this case, we had to enclose our constraint names in double quotes, i. Here’s a basic example of how to remove a constraint named ‘user_email_key’ from a table called ‘users’: It’s important to know the exact name of the constraint. Yes, you can. I need to display the list of integrity constraints of my solution by indicating the name of the constraint, its type and the detail of the constraint (message that explains what validates the constraint), all sorted by table name and constraint name. However, it does not give the table that this constraint is defined on. (At present, only b-tree supports it. Jan 20, 2023 · Is there a way to get the SQL for constraints in PostgreSQL? I'm not seeing a pg_constraints table and the information I'm finding on line isn't pointing me to a solution, for example, these are some of the hits coming up when I Google the terms (postgresql get sql for constraint). It cannot have more than one primary key. constraint_column_usage. nspname AS schema ,proname AS sproc_name ,proargnames AS arg_names ,t. Indexes can also be used to enforce uniqueness of a column's value, or the uniqueness of the combined values of more than one column. Oct 18, 2015 · 1. Some of the frequently used data types are integer for whole numbers, numeric for possibly fractional numbers, text for character strings, date for dates, time for time-of-day values, and Aug 29, 2022 · This query would get you information about the coderpad database, like the database owner. 10. Problem is, it errors out at modify as it does not recognize the keyword. CREATE TABLE Item( Item_no integer UNIQUE, Name text, ); 2) NOT Null Constraints. I did the following (from here and the documentation). Table 37. table_constraints Columns. 04. A not-null constraint defines that a column should never be a null value. SET session_replication_role = replica; Both tricks won't work for non-deferrable constraints and check constraints. A table can have zero or one primary key. conrelid = cls. contype = 'f') then kcu. In fact, other options are not needed. serial is not a "real" data type, it's a short hand for populating the default value from sequence. oid = c. ) You must own the view to use ALTER VIEW. p - primary key, f - foreign key, u - unique, Feb 10, 2024 · Execution Constraint; 1) PostgreSQL Unique Constraint. Recall the weather and cities tables from Chapter 2. oid = p. Range types are data types representing a range of values of some element type (called the range's subtype ). user_id | group_id. Using multiple statements within a transaction works on all SQL dbms that support using this DDL in a transaction. I found a solution: SELECT routine_definition FROM information_schema. g. Introduction to PostgreSQL primary key. description ,pg_get_functiondef(p. This guide will provide you with an in-depth understanding of PRIMARY KEY constraints in PostgreSQL. It's valid for me to do so using the database to check it, or to check it in code. A check constraint uses a boolean expression to evaluate the values, ensuring that only valid data I have checked the documentation provided by Oracle and found a way to modify a constraint without dropping the table. Constraints could be column level or table level. To drop a constraint, you will use the ALTER TABLE command followed by DROP CONSTRAINT, and then specify the name of the constraint. . Aug 28, 2012 · Here is a complete sample query using pg_get_functiondef: WITH funcs AS ( SELECT n. They ensure that the data is consistent, accurate, and reliable. 4. This is the query I am using, ALTER TABLE Alerts ADD CONSTRAINT DF_Alerts_bIsActive SET DEFAULT ((1)) FOR bIsActive; Aug 12, 2021 · A CHECK constraint does the job. 0-1ubuntu1~18. 17. As you can see above, add unique constraint name in the Name textbox. Introduction to PostgreSQL identity column. pg_constraint with the view pg_class ( JOIN pg_class t ON t. A constraint is an SQL object that helps define the set of valid values in the table in various ways. 53. Plus, that information can be picked up by information_schema to do some metadata inferring if necessary on the fact that both need to be unique. Constraints in PostgreSQL. In psql command line tool, \d table_name or \d+ table_name to find the information on columns of a table. The column that participates in the primary key is known as the primary key column. objoid JOIN pg_namespace n on n. CREATE UNIQUE INDEX name ON table ( column [, ]) [ NULLS [ NOT ] DISTINCT ]; Currently, only B-tree indexes can be declared unique. user_id int primary key, group_id int references groups on update cascade. The first two are not limited, but the documentation for constraint_column_usage tells you: The view constraint_column_usage identifies all columns in the current database that are used by some constraint. Results in constraint_catalog, constraint_schema, constraint_name, check_clause. Unique constraint enforces unique values for a column or group of columns across the whole table. To get constaint name write (in psql): \d tableName. But if you have non-unique entries in your table, it will fail. pg_constraint #. nspname = 'public' Apr 30, 2018 · I am working with PostgreSQL database. May 9, 2017 · The problem is that doing. Jul 12, 2018 · String Format Constraint On PostgreSQL Column Not Working. From documentation this example: ALTER TABLE distributors. typname AS return_type ,d. Mar 18, 2020 · Database: PostgreSQL 9. : ALTER TABLE name RENAME CONSTRAINT "FK_constraint_name" TO "FK_new_constraint_name"; Jun 18, 2024 · The CONSTRAINT. Query below lists check constraints defined in the database ordered by constraint name. fk_columns - list of FK colum names, separated with "," constraint_name - foreign key constraint name. The MetaData. Create a new database and project directory. The SQL tab displays the SQL code generated by dialog selections. 2. Sep 23, 2023 · A PRIMARY KEY constraint is one of the most essential elements in relational database management. A not-null constraint is functionally equivalent to creating a check constraint CHECK (column_name IS NOT NULL), but in PostgreSQL creating an explicit not-null constraint is more efficient. Unique constraints help you ensure that the data contained in a column, or a group of column constraints is unique. phase_steps ( phase_step_id integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY , step_type text , step_status text , CONSTRAINT step_status_for_step_type CHECK ( step_type = 'RESEARCH' AND step_status IN ('COMPLETE Feb 13, 2015 · 2. (Column constraints are not treated specially. oid WHERE relname='table_name'; Replace 'table_name' with the name of the table for which you want to list constraints. Tables are included in pg_class and columns in pg_attributes. if the constraint that was violated is named orders_customer_id_fkey then the following show you that constraint: select pg_get_constraintdef(c. SELECT statement to query the column_names,datatype,character maximum length of the columns table in the information_schema database; Sep 14, 2019 · Column constraint definition as a string; Foreign keys; I can get more data from postgresql internal tables preferably from the information squema. Every time the user inserts a new row, PostgreSQL checks if the value already exists in the table if UNIQUE constraints are used. column_name else ccu. To change a view's schema, you must also have CREATE privilege on the new schema. table_name else (null) end as reference May 28, 2012 · 3. views WHERE table_schema = 'information_schema' AND table_name = 'views'; Feb 17, 2015 · Yes the syntax is "correct". constraint_column_usage AS ccu. 3. An access method that supports this feature sets amcanunique true. Next. mydomain ) then the domain is created in the specified schema. select n. This ensures the accuracy and reliability of the data in the database. This way, a unique index will be created behind the scenes, and you will get the behavior you need. (If you want to modify the view's defining query, use CREATE OR REPLACE VIEW . Indexing. Not Null Constraint: The NOT NULL constraint restricts the NULL value in the column. Sep 15, 2021 · The problem with your approach is that your constraints are not full. Join the view pg_catalog. It has the syntax regexp_match ( string, pattern [, flags ]). Chapter 64. String in Postgres; validation of the contents of a string. The information schema consists of a set of views that contain information about the objects defined in the current database. Check this query to see them organized by table. May 30, 2013 · You use three relations in your query: table_constraints. rolname AS "Owner". Think of it like a generalised UNIQUE constraint: instead of "no two rows can be equal", you can say things like "no two rows overlap", or even "no two rows can be different". To find the name of a constraint in PostgreSQL, use the view pg_constraint in the pg_catalog schema. In this case the data type is tsrange (short for “timestamp range The solution is here. The FOREIGN KEY (aka parent) column has to already exist in order to make it an FK. DROP CONSTRAINT [ IF EXISTS ] constraint_name [ RESTRICT | CASCADE ] Jan 4, 2024 · The following command shows how to add a unique constraint to the email column of the users table: ALTER TABLE users. ) Not-null constraints are represented in the pg_attribute catalog, not here. Description. drop constraint table1_id_check; alter table table1. Mar 19, 2013 · No need to parse pg_get_constraintdef(), just use columns of pg_constraint table to obtain other details (). conname as constraint_name. ALTER TABLE students. Example. public_insurer_credit MODIFY CONSTRAINT public_insurer_credit_fk1 deferrable, initially deferred; Sep 29, 2023 · You can use the following syntax to remove the primary key constraint. Constraints on Ranges. #. Tested in PG 9. Here is the how to add a unique constraint to your table in PostgreSQL 9. Nov 25, 2013 · I have this simple contraint set on my sales table CONSTRAINT sales_stamping_id_key UNIQUE (company_id, stamping_id, invoice_number, billed) and i can't seem to find a way to change this constraint to deferrable without deleting the constraint. Warning: If you have other triggers they will also be disabled. Aug 14, 2018 · Here is PostgreSQL specific answer. PostgreSQL version 10 introduced a new constraint GENERATED AS IDENTITY that allows you to automatically assign a unique number to a column. Primary Key May 2, 2020 · PostgreSQL exposes the constraints as well as other schema details through information_schema, so to find all the constraints for the table, query table_constraints, for example: SELECT constraint_name FROM information_schema. In this section, we’ll explore various types of constraints in PostgreSQL and how to implement them. ALTER TABLE DISABLE TRIGGER ALL; To disable all such constraints for the duration of a database session, you can. add constraint table1_id_check CHECK (Id ~ '^[a-z0-9]{3,}$'); PostgreSQL lets you use multiple clauses within an ALTER TABLE statement. FROM pg_database d. If a check constraint, an internal representation of the expression. When a primary key is defined, it is sufficient to just reference the column name; which is the dominant example one tends to find. Column Type. conbin pg_node_tree. A column can have multiple constraints. constraint_name where constraint_type = 'FOREIGN KEY' Sep 12, 2023 · You can use it to describe a table with the query below: 1 SELECT 2 column_name, 3 data_type 4 FROM 5 information_schema. Column level constraints are applied only to one column whereas table level constraints Jun 27, 2024 · A not-null constraint is always written as a column constraint. 1 | 10. oid = d. ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5) NO INHERIT; You will have to replace constraint name as well as table name and content by your local requirements. PostgreSQL enforces SQL uniqueness constraints using unique indexes, which are indexes that disallow multiple entries with identical keys. alter table table1. Jun 21, 2019 · The simplest form of the TRUNCATE TABLE statement is as follows: TRUNCATE TABLE table_name; Remove all data from table that has foreign key references. ALTER TABLE tableName. pg_get_constraintdef () A function returning the definition of a constraint. 9. I have to apply default constraint to one of my columns whose default value should be 1. I need to return foreign key constraints defined in a database and I tried the below query but no results and I run it remotely by pgAdmin V. cd check-demo. Constraints are the rules enforced on data columns on table. WHERE conrelid =. constraint_name. ALTER TABLE table_name ADD constraint_name constraint_definition IF NOT EXISTS; For example, the following statement would add a constraint to ensure that the `email` column in the `users` table contains a valid email address: sql. Make sure the modifications don't violate the constraints. It uniquely identifies each row in a database table and ensures that the column (s) designated as a PRIMARY KEY contains unique, non-NULL values. pgdg18. oid JOIN pg_description d on p. an upper-case prefix. table_schema as table_schema, ccu. constraint_name = tc. Constraints can be specified as part of the table definition. In our example, we select the constraints from the table student ( WHERE t SQL Query to Find Constraint Names. 4 The optional constraint clauses specify constraints (tests) that new or updated rows must satisfy for an insert or update operation to succeed. table_name, ccu. foreign_table - foreign table schema and name. 2. FROM information_schema. For instance, ranges of timestamp might be used to represent the ranges of time that a meeting room is reserved. A foreign key establishes a link between the data in two tables by referencing the primary key or a unique constraint of the referenced table. table_name as table_name, case when (pgc. The catalog pg_constraint stores check, primary key, unique, foreign key, and exclusion constraints on tables. Consider the following problem: You want to make sure that no one can insert rows in the weather table that do not have a matching entry in the cities table. 5. Using EMS SQL Manager for PostgreSQL. constraint_table_usage. Oct 3, 2019 · I am searching for a way to display a command that creates a certain routine in PostgreSQL. prorettype = t. 52. Unique Constraint. The name will be displayed in the pgAdmin tree control. ADD CONSTRAINT unique_email. views view by running: SELECT view_definition FROM information_schema. Example: group_id int primary key. nspname 37. select *. The optional constraint clauses specify constraints (tests) that new or updated rows must satisfy for an insert or update operation to succeed. You can do what you are already thinking of: create a unique constraint on both fields. The GENERATED AS IDENTITY constraint is the SQL standard-conforming variant of the good old SERIAL column. Likewise, if you want to set a default value for a Boolean column when you create a table, you use the DEFAULT constraint in the column definition as follows: CREATE TABLE boolean_demo ( is_ok BOOL DEFAULT 't'); Code language: SQL (Structured Query Language) (sql) Summary. (SELECT oid. table_constraints. FOREIGN KEY directive is used to create the constraint in an “inline” fashion within the CREATE TABLE definition. Postgres Check Constraint definition. 0, 64-bit. A check constraint allows you to enforce data integrity rules at the database level. ON ccu. 2) PostgreSQL DESCRIBE TABLE using information_schema. conrelid) and use the relname column to filter the constraints by table name. A domain is essentially a data type with optional constraints (restrictions on the allowed set of values). Jun 29, 2016 · In Postgres (and other RDBMs) cascading updates apply exclusively to foreign keys. Use the PostgreSQL BOOLEAN datatype to store the boolean data. To get the coderpad owner who initially created the database, you’d use this query: SELECT a. 3. table_name FROM information_schema. These are used to prevent invalid data from being entered into the database. Jul 9, 2018 · Whereas a CHECK constraint evaluates an expression based on a single row of the table, an EXCLUDE constraint evaluates a comparison of two rows in the table. Mar 12, 2016 · You just have to add another step - in fact PostgreSQL is already telling you that: column "sender" referenced in foreign key constraint does not exist. contype as constraint_type, ccu. The correct column is ordinal_position . Dec 12, 2018 · Columns. connamespace where conname = 'orders_customer_id_fkey' and n. DROP CONSTRAINT constraintName; Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) Now let’s remove the primary key constraint that we created in the previous example. 11. pg_get_constraintdef() is a system function for obtaining the definition of a constraint. Now I have to alter table columns as per constraints. Here's an example SQL statement. I want to check the constraint before making an insert with that data. In this case, it returns the string 10, which references the OID in the pg_authid catalog. table_constraints tc inner join information_schema. For example: CONSTRAINT field_a_check CHECK (thematic::text ~~ 'A'::text AND field_a IS NOT NULL), The constraint says "the record is ok if thematic contains 'A' and field_a is not empty". pg_constraint. The regexp_match function returns a text array of matching substring (s) within the first match of a POSIX regular expression pattern to a string. x: CREATE UNIQUE INDEX constraint_name ON table_name (columns); My solution is to log in to the postgres db using psql with the -E option as follows: psql -E -U username -d database In psql, run the following commands to see the sql that postgres uses to generate Add Unique Constraint. In the popup, go to 'Constraints' tab where you can add or edit Primary key, Foreign Key, Check, and unique constraints, as shown below. table_constraints WHERE table_name='my_table' AND constraint_type='UNIQUE'; Jan 5, 2024 · Dropping Constraints: The Basics. e. A primary key is a column or a group of columns used to uniquely identify a row in a table. oid They are called Inline Constraints. To get a list of all constraint names associated with a table, you can run the following SQL query: SELECT conname AS constraint_name FROM pg_constraint INNER JOIN pg_class ON conrelid=pg_class. If it discovers that the new value is already PostgreSQL allows you to create a UNIQUE constraint to a group of columns using the following syntax: c1 data_type, c2 data_type, c3 data_type, UNIQUE (c2, c3) The combination of values in the columns c2 and c3 will be unique across the whole table. oid = pgc. connamespace join pg_class cls on pgc. The information schema is defined in the SQL standard and can therefore be expected to be portable and remain stable — unlike the system catalogs, which are specific to PostgreSQL and are Dec 27, 2011 · The docs advocate this method, Adding a unique constraint will automatically create a unique B-tree index on the column or group of columns listed in the constraint. Query select pgc. You can add constraints using pgAdmin by right clicking on the table and select 'Properties' in the context menu. The Foreign key dialog organizes the development of a foreign key constraint through the following dialog tabs: General, Definition, Columns, and Action. 1) 7. Data Types. create_all() and MetaData. relname as table_name, c. This will open a popup where you can add or edit multiple columns definition. Aug 14, 2020 · I would suggest that you modify your data model to have a table, PollOptions: CREATE TABLE IF NOT EXISTS PollOptions ( PollOptionsId SERIAL PRIMARY KEY, -- should use generated always as identity PollId INT NOT NULL, REFERENCES Polls(id), OptionNumber int, Option text, UNIQUE (PollId, Option) ); Jan 20, 2012 · position_in_unique_constraint indicates position for FOREIGN key, it is always null for primary keys. There are two ways to define constraints: table constraints and column constraints. check_constraints. The view table_constraints contains all constraints belonging to tables that the current user owns or has some privilege other than SELECT on. Consider the following scenario: CREATE DOMAIN dom_zipcode AS text; ALTER DOMAIN dom_zipcode. Apr 27, 2016 · The ON CONFLICT clause needs a single unique constraint when we ask it to DO UPDATE. WHERE constraint_type = 'FOREIGN KEY' AND ccu. Use the Name field to add a descriptive name for the foreign key. (one to many association ) Here is a code snippet for a model client. consrc as definition from pg_constraint pgc join pg_namespace nsp on nsp. (It's recommended to use pg_get_constraintdef() to extract the definition of a check constraint. 37. About Us. The client has many environments. FROM user_constraints. The check_clause is what I want and this table also gives me the constraint_schema. key_column_usage. oid) as definition FROM pg_proc p JOIN pg_type t on p. oid, true) from pg_constraint c join pg_namespace n on n. The constraints can be queried via pg_constraint. table_name='YourTableNameHere'; This will list all the tables that use your specified table as a foreign key. 77 9. HumanoVirtual. The following illustrates the syntax of the GENERATED 1. Nov 25, 2013 · Adding one more option: right-click desired database > generate ERD (Beta) > Generate SQL (or Alt+Ctrl+S) and pgAdmin 4 will open Query Editor where you can find all tables with column names and data types: answered Sep 20, 2021 at 8:20. You can add a new constraint with with alter table command. Alter table public. 13. The user who defines a domain becomes its owner. Foreign Keys #. nspname as schema_name, t. A not-null constraint is always written as a column constraint. It will retrieve all columns and their relationship as well: select *FROM ( from ( select pgc. Here constraint_type can be:. gw yk nd uk wa lx uu fd xw wl