PostgreSQL error 42P12 invalid_database_definition appears when a CREATE DATABASE statement contains incompatible or unsupported parameters.
invalid_database_definition (PostgreSQL 42P12) triggers when CREATE DATABASE includes conflicting locale, encoding, or tablespace options. Align LC_COLLATE, LC_CTYPE, ENCODING, and TABLESPACE with the template database, then rerun CREATE DATABASE to resolve the error.
invalid_database_definition
PostgreSQL raises error code 42P12, condition name invalid_database_definition, when the CREATE DATABASE command contains an option combination the server cannot honor.
The error typically appears immediately after you run CREATE DATABASE with conflicting ENCODING, LC_COLLATE, LC_CTYPE, or TABLESPACE clauses. PostgreSQL validates these parameters before creating the new database and aborts if they mismatch the template database or are not supported.
Incompatible locale and encoding pairs cause most 42P12 errors.
For example, specifying ENCODING 'UTF8' with LC_COLLATE 'C' in a cluster built for a different locale fails validation.
Attempting to create a database in a tablespace not allowed for that encoding or collation also triggers the error. Wrong template database selections and deprecated CREATE DATABASE syntax can contribute.
First, examine the existing clusters default locale and encoding with \l or SELECT name, encoding, datcollate, datctype FROM pg_database WHERE datname = 'template0';.
Align your CREATE DATABASE statement with these values.
When you need a different locale, create the new database from template0 and supply matching LC_COLLATE and LC_CTYPE values that the operating system supports. Always verify the chosen tablespace exists and has proper permissions.
Scenario 1: LC_COLLATE and LC_CTYPE mismatch. Solution: Repeat CREATE DATABASE with matching locale values.
Scenario 2: Unsupported ENCODING on the host OS.
Solution: Use ENCODING names returned by SHOW SERVER_ENCODING.
Set cluster-wide locale and encoding correctly during initdb so future CREATE DATABASE calls inherit valid defaults.
Use template0 for special locales, and check available collations with SELECT * FROM pg_collation.
invalid_parameter_value (22023) arises when a single option is wrong, not the combination.
duplicate_database (42P04) occurs when the database name already existsfix by dropping or renaming.
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No. PostgreSQL only uses error code 42P12 during CREATE DATABASE validation.
Run SELECT * FROM pg_collation ORDER BY collname; to see available collations.
Yes. Galaxys AI copilot validates CREATE DATABASE syntax and warns about mismatched locale or encoding before execution.
Template0 is read only and contains no locale assumptions, making it safe for custom collations, but you must specify all options explicitly.
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