The LDB (Linked-list database) is a headless database management system focused in single-key, read-only application on vast amounts of data, while maintaining a minimal footprint and keeping system calls to a bare minimum. Information is structured using linked lists.
Building LDB requires openssl and zlib. Make sure packages zlib1g-dev and libssl-dev are installed.
Run make to build the shell binary and the shared library.
Run make install to copy the binary to /usr/bin, the shared library to /usr/lib and the header to /usr/include.
Some of the features of the LDB are:
- Single, fixed size, numeric key (32-bit)
- Single-field records
- Larger keys also are supported by storing exceeded data keys in the data record.
- No indexing: Mapping
- Data tables define either fixed or variable-length data records
- Read-only
- Database updates are performed in a single-threaded, non-disruptive batch operation
- Zlib data compression
- Data records are organized in a linked list
- C library for native development
- LDB shell allows interaction with external languages
create database DBNAME
Creates an empty database
create table DBNAME/TABLENAME keylen N reclen N
Creates an empty table in the given database with
the specified key length (>= 4) and record length (0=variable)
show databases
Lists databases
show tables from DBNAME
Lists tables from given database
insert into DBNAME/TABLENAME key KEY hex DATA
Inserts data (hex) into given db/table for the given hex key
insert into DBNAME/TABLENAME key KEY ascii DATA
Inserts data (ASCII) into db/table for the given hex key
select from DBNAME/TABLENAME key KEY
Retrieves all records from db/table for the given hex key (hexdump output)
select from DBNAME/TABLENAME key KEY ascii
Retrieves all records from db/table for the given hex key (ascii output)
select from DBNAME/TABLENAME key KEY csv hex N
Retrieves all records from db/table for the given hex key (csv output, with first N bytes in hex)
delete from DBNAME/TABLENAME max LENGTH keys KEY_LIST
Deletes all records for the given comma separated hex key list from the db/table. Max record length expected
collate DBNAME/TABLENAME max LENGTH
Collates all lists in a table, removing duplicates and records greater than LENGTH bytes
merge DBNAME/TABLENAME1 into DBNAME/TABLENAME2 max LENGTH
Merges tables erasing tablename1 when done. Tables must have the same configuration
unlink list from DBNAME/TABLENAME key KEY
Unlinks the given list (32-bit KEY) from the sector map
dump DBNAME/TABLENAME hex N
Dumps table contents with first N bytes in hex
The following example explains how to create a database, a table, a record, and querying that record.
$ echo "create database test" | ldb
OK
$ echo "create table test/table1 keylen 16 reclen variable" | ldb
OK
$ echo "insert into test/table1 key 26e3a3bd01585cde84408f01fe981f6a ascii THIS_IS_A_TEST" | ldb
$ echo "select from test/table1 key 26e3a3bd01585cde84408f01fe981f6a" | ldb
0000 544849535f49535f415f54455354 THIS_IS_A_TEST
$ echo "select from test/table1 key 26e3a3bd01585cde84408f01fe981f6a ascii" | ldb
THIS_IS_A_TEST
The LDB is released under the GPL 2.0 license. See the LICENSE file for more infomation.
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