PostgreSQL add UNIQUE key
When you add a UNIQUE constraint to a column or a group of columns, ... CREATE TABLE person ( id SERIAL PRIMARY KEY, first_name VARCHAR (50), ... ,When you define a primary key or a unique constraint for a table, PostgreSQL automatically ... ALTER TABLE employees ADD mobile_phone VARCHAR(20);. ,When you add a primary key to a table, PostgreSQL creates a unique B-tree index on the column or a group of columns used to define the primary key. Define ... ,This PostgreSQL tutorial explains how to create, add, and drop unique constraints in ... What is the difference between a unique constraint and a primary key? ,2011年9月7日 — Yes, you can add a UNIQUE constraint after the fact. However, if you have non-unique entries in your table Postgres will complain about it until ... ,2013年1月8日 — CREATE TABLE someTable ( id serial PRIMARY KEY, col1 int NOT NULL, col2 ... If col1 and col2 make a unique and can't be null then they make a good primary key: ... ALTER TABLE someTable ADD UNIQUE (col1, col2). ,The index covers the columns that make up the primary key or unique ... Note: The preferred way to add a unique constraint to a table is ALTER TABLE ... ADD ... ,PostgreSQL automatically creates a unique index when a unique constraint or primary key is defined for a table. The index covers the columns that make up the ... ,ADD table_constraint_using_index. This form adds a new PRIMARY KEY or UNIQUE constraint to a table based on an existing unique index. All the columns of ... ,A check constraint consists of the key word CHECK followed by an ... Adding a primary key will automatically create a unique B-tree index on the column or ...
| 相關軟體 PostgreSQL (64-bit) 資訊 | |
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 PostgreSQL add UNIQUE key 相關參考資料
PostgreSQL UNIQUE Constraint - PostgreSQL Tutorial
When you add a UNIQUE constraint to a column or a group of columns, ... CREATE TABLE person ( id SERIAL PRIMARY KEY, first_name VARCHAR (50), ... https://www.postgresqltutorial PostgreSQL UNIQUE Index - PostgreSQL Tutorial
When you define a primary key or a unique constraint for a table, PostgreSQL automatically ... ALTER TABLE employees ADD mobile_phone VARCHAR(20);. https://www.postgresqltutorial PostgreSQL Primary Key - PostgreSQL Tutorial
When you add a primary key to a table, PostgreSQL creates a unique B-tree index on the column or a group of columns used to define the primary key. Define ... https://www.postgresqltutorial PostgreSQL: Unique Constraints - TechOnTheNet
This PostgreSQL tutorial explains how to create, add, and drop unique constraints in ... What is the difference between a unique constraint and a primary key? https://www.techonthenet.com Can I add a UNIQUE constraint to a PostgreSQL table, after it's ...
2011年9月7日 — Yes, you can add a UNIQUE constraint after the fact. However, if you have non-unique entries in your table Postgres will complain about it until ... https://stackoverflow.com In Postgresql, force unique on combination of two columns ...
2013年1月8日 — CREATE TABLE someTable ( id serial PRIMARY KEY, col1 int NOT NULL, col2 ... If col1 and col2 make a unique and can't be null then they make a good primary key: ... ALTER TABLE someTable A... https://stackoverflow.com Documentation: 9.3: Unique Indexes - PostgreSQL
The index covers the columns that make up the primary key or unique ... Note: The preferred way to add a unique constraint to a table is ALTER TABLE ... ADD ... https://www.postgresql.org Documentation: 9.4: Unique Indexes - PostgreSQL
PostgreSQL automatically creates a unique index when a unique constraint or primary key is defined for a table. The index covers the columns that make up the ... https://www.postgresql.org Documentation: 9.1: ALTER TABLE - PostgreSQL
ADD table_constraint_using_index. This form adds a new PRIMARY KEY or UNIQUE constraint to a table based on an existing unique index. All the columns of ... https://www.postgresql.org Documentation: 9.4: Constraints - PostgreSQL
A check constraint consists of the key word CHECK followed by an ... Adding a primary key will automatically create a unique B-tree index on the column or ... https://www.postgresql.org |