Is there a hstore module in PostgreSQL?
This documentation is for an unsupported version of PostgreSQL. You may want to view the same page for the current version, or one of the other supported versions listed above instead. This module implements the hstore data type for storing sets of key/value pairs within a single PostgreSQL value.
When to use sort ordering for hstore columns?
This allows hstore columns to be declared UNIQUE, or to be used in GROUP BY, ORDER BY or DISTINCT expressions. The sort ordering for hstore values is not particularly useful, but these indexes may be useful for equivalence lookups. Create indexes for = comparisons as follows:
How are keys and values represented in hstore?
Keys and values are simply text strings. The text representation of an hstore , used for input and output, includes zero or more key => value pairs separated by commas. Some examples: The order of the pairs is not significant (and may not be reproduced on output). Whitespace between pairs or around the => sign is ignored.
Which is an example of the use of hstore?
For example: hstore also supports btree or hash indexes for the = operator. This allows hstore columns to be declared UNIQUE, or to be used in GROUP BY, ORDER BY or DISTINCT expressions. The sort ordering for hstore values is not particularly useful, but these indexes may be useful for equivalence lookups.
How are keys and values represented in PostgreSQL?
This can be useful in various scenarios, such as rows with many attributes that are rarely examined, or semi-structured data. Keys and values are simply text strings. The text representation of an hstore , used for input and output, includes zero or more key => value pairs separated by commas.
What are the double quote keys in PostgreSQL?
Double-quote keys and values that include whitespace, commas, = s or > s. To include a double quote or a backslash in a key or value, escape it with a backslash. Each key in an hstore is unique. If you declare an hstore with duplicate keys, only one will be stored in the hstore and there is no guarantee as to which will be kept:
Is the null keyword case insensitive in PostgreSQL?
The NULL keyword is case-insensitive. Double-quote the NULL to treat it as the ordinary string “NULL”. Note: Keep in mind that the hstore text format, when used for input, applies before any required quoting or escaping. If you are passing an hstore literal via a parameter, then no additional processing is needed.