PostgreSQL supports a TIMESTAMP data type that is used to store the DateTime values in the database. In PostgreSQL, “NULL” is used as the column’s default value, if no default value is explicitly declared. However, if a particular value is assigned as the column’s default value, ...
PostgreSQL COALESCE Function: Handling Null Values In PostgreSQL, the COALESCE function is used to handle NULL values by returning the first non-NULL value from a list of arguments. It’s especially useful for ensuring that queries return usable data, even when some values are missing or undefine...
What is NULLIF() and How to Use it in PostgreSQL? It is a built-in function in Postgres that accepts a couple of arguments and retrieves a NULL value if both arguments are equal or if either of the specified arguments is NULL. It retrieves the first argument if both arguments are not...
update, delete, and select queries. We have used null when we want to check that a given value is null or not null; the given condition returns the true value when the given value is null in PostgreSQL. It is used when one or more fields of the table are set as blank. ...
we keep seeing DBAs tending to disable the autovacuum altogether and invite a bigger set of problems and even outages. At the very least, my request to anyone who is new to PostgreSQL is, please never try to turn off the autovacuum. That’s not the way to address autovacuum-related issues...
Logical Replication是PostgreSQL10.0引入的内置新特性,而pglogical则是一个插件。PG10版本之前可以使用该插件进行逻辑复制,通过持续发展,pglogical的所有特性都集成到了Logical Replication中。换句话说,pglogical插件变成了Logical Replication。Logical Replication最基本的优势在于不用安装任何插件,安装插件受限的环境中,可以推荐...
Replication_timeout is detection time for the replication cuts it, and wal_receiver_status_interval is an interval when HS tries connecting to PRI. To shorten detection, you should set this value to small. When using rep_mode=sync, RA adds "include" into postgresql.conf to switch replication...
INSERTINTOdepartmentsvalues(30,'Sales',null,null); UPDATE Statement Using an UPDATE statement a user can modify an existing row. Syntax UPDATEtable_nameSETcolumn1 = value1, column2 = value2, ...WHEREcondition; Example 1 Modify a value department id to 50 for an employ...
Explore two different approaches of PostgreSQL list users in this blog: with a command-line command and with a query. Let’s learn how to list users in Postgres!
Not NULL:This constraint does not allow us to insert NULL value in the column on which it is created UNIQUE:The UNIQUE constraint does not allow duplicate values to be inserted in the column CHECK: This constraint checks the value being inserted in a table. The check constraint has expression...