(And they are probably not useful for anything else.) initdb uses a BKI file to do part of its job when creating a new database cluster.

The input file used by initdb is created as part of building and installing PostgreSQL by a program named genbki.sh from some specially formatted C header files in the source tree.

The created BKI file is called postgres.bki and is normally installed in the share subdirectory of the installation tree.

Related information may be found in the documentation for initdb.

BKI File Format

This section describes how the PostgreSQL backend interprets BKI files. This description will be easier to understand if the postgres.bki file is at hand as an example. You should also study the source code of initdb to get an idea of how the backend is invoked.

BKI input consists of a sequence of commands. Commands are made up of a number of tokens, depending
on the syntax of the command. Tokens are usually separated by whitespace, but need not be if there is no ambiguity.

There is no special command separator; the next token that syntactically cannot belong to the preceding command starts a new one. (Usually you would put a new command on a new line, for clarity.) Tokens can be certain key words, special characters (parentheses, commas, etc.), numbers, or double-quoted strings.

Everything is case sensitive.

Lines starting with a # are ignored.


BKI Commands

open tablename

Open the table called tablename for further manipulation.

close [tablename]

Close the open table called tablename. It is an error if tablename is not already opened. If no

tablename is given, then the currently open table is closed.
create tablename (name1 = type1 [, name2 = type2, ...])

Create a table named tablename with the columns given in parentheses.

The type is not necessarily the data type that the column will have in the SQL environment; that is determined by the pg_attribute system catalog. The type here is essentially only used to allocate storage. The following types are allowed: bool, bytea, char (1 byte), name, int2, int2vector, int4, regproc, text, oid, tid, xid, cid, oidvector, smgr, _int4 (array), _aclitem (array).

Array types can also be indicated by writing [] after the name of the element type.

Note: The table will only be created on disk, it will not automatically be registered in the system catalogs and will therefore not be accessible unless appropriate rows are inser ted in pg_class, pg_attribute, etc.

insert [OID = oid_value] (value1 value2 ...)

Insert a new row into the open table using value1, value2, etc., for its column values and oid_value for its OID. If oid_value is zero (0) or the clause is omitted, then the next available

OID is used.

NULL values can be specified using the special key word _null_. Values containing spaces must be double quoted.

declare [unique] index indexname on tablename using amname (opclass1 name1 [, ...])

Create an index named indexname on the table named tablename using the amname access method. The fields to index are called name1, name2 etc., and the operator classes to use are op-class1, opclass2 etc., respectively.
build indices

Build the indices that have previously been declared.

Example

The following sequence of commands will create the test_table table with the two columns cola and colb of type int4 and text, respectively, and insert two rows into the table.

create test_table (cola = int4, colb = text)
open test_table
insert OID=421 ( 1 "value1" )
insert OID=422 ( 2 _null_ )
close test_table