[![EJDB](https://raw.github.com/Softmotions/ejdb/master/misc/ejdblogo3.png)](http://ejdb.org) Embedded JSON Database engine ==================================== It aims to be a fast [MongoDB](http://mongodb.org)-like library **which can be embedded into C/C++/NodeJS/Python/Lua/Java applications under terms of LGPL license.** EJDB is the C library based on modified version of [Tokyo Cabinet](http://fallabs.com/tokyocabinet/). JSON representation of queries and data implemented with API based on [C BSON](https://github.com/mongodb/mongo-c-driver/tree/master/src/) News =============================== * `2013-04-03` **[Java API binding available](https://github.com/Softmotions/ejdb/blob/master/jejdb/)** * `2013-03-20` **[Lua binding available](https://github.com/Softmotions/ejdb/blob/master/luaejdb/)** * `2013-02-15` **[EJDB Python3 binding available](https://github.com/Softmotions/ejdb/blob/master/pyejdb/)** * `2013-02-07` **[Debian packages provided](https://github.com/Softmotions/ejdb/wiki/Debian-Ubuntu-installation)** * `2013-01-22` **[Collection joins now supported](https://github.com/Softmotions/ejdb/wiki/Collection-joins)** Features ================================ * LGPL license allows you to embed this library into proprietary software. * MongoDB-like queries and overall philosophy. * Collection level write locking. * Collection level transactions. * String token matching queries: ```$stror``` ```$strand``` * [Node.js](http://nodejs.org) binding * [Collection joins](https://github.com/Softmotions/ejdb/wiki/Collection-joins) * Python binding * Lua binding * Java binding EJDB C Library ================================== One snippet intro ----------------------------------- ~~~~~~ #include static EJDB *jb; int main() { jb = ejdbnew(); if (!ejdbopen(jb, "addressbook", JBOWRITER | JBOCREAT | JBOTRUNC)) { return 1; } //Get or create collection 'contacts' EJCOLL *coll = ejdbcreatecoll(jb, "contacts", NULL); bson bsrec; bson_oid_t oid; //Insert one record: //JSON: {'name' : 'Bruce', 'phone' : '333-222-333', 'age' : 58} bson_init(&bsrec); bson_append_string(&bsrec, "name", "Bruce"); bson_append_string(&bsrec, "phone", "333-222-333"); bson_append_int(&bsrec, "age", 58); bson_finish(&bsrec); //Save BSON ejdbsavebson(coll, &bsrec, &oid); fprintf(stderr, "\nSaved Bruce"); bson_destroy(&bsrec); //Now execute query //QUERY: {'name' : {'$begin' : 'Bru'}} //Name starts with 'Bru' string bson bq1; bson_init_as_query(&bq1); bson_append_start_object(&bq1, "name"); bson_append_string(&bq1, "$begin", "Bru"); bson_append_finish_object(&bq1); bson_finish(&bq1); EJQ *q1 = ejdbcreatequery(jb, &bq1, NULL, 0, NULL); uint32_t count; TCLIST *res = ejdbqryexecute(coll, q1, &count, 0, NULL); fprintf(stderr, "\n\nRecords found: %d\n", count); //Now print the result set records for (int i = 0; i < TCLISTNUM(res); ++i) { void *bsdata = TCLISTVALPTR(res, i); bson_print_raw(bsdata, 0); } fprintf(stderr, "\n"); //Dispose result set tclistdel(res); //Dispose query ejdbquerydel(q1); bson_destroy(&bq1); //Close database ejdbclose(jb); ejdbdel(jb); return 0; } ~~~~~~ You can save this code in `csnippet.c` And build: ```sh gcc -std=c99 -Wall -pedantic -c -o csnippet.o csnippet.c gcc -o csnippet csnippet.o -ltcejdb ``` Building & Installation -------------------------------- [Installing on Debian/Ubuntu](https://github.com/Softmotions/ejdb/wiki/Debian-Ubuntu-installation) Manual installation ------------------------------- ### Prerequisites **System libraries:** * gcc * zlib-dev ### Build and install ~~~~~~ cd ./tcejdb ./configure --prefix= && make && make check make install ~~~~~~ * library name: **tcejdb** (with pkgconfig) * main include header: `````` C API --------------------------------- EJDB API presented in **[ejdb.h](https://github.com/Softmotions/ejdb/blob/master/tcejdb/ejdb.h)** C header file. JSON processing API: **[bson.h](https://github.com/Softmotions/ejdb/blob/master/tcejdb/bson.h)** Queries --------------------------------- ~~~~~~ /** * Create query object. * Sucessfully created queries must be destroyed with ejdbquerydel(). * * EJDB queries inspired by MongoDB (mongodb.org) and follows same philosophy. * * - Supported queries: * - Simple matching of String OR Number OR Array value: * - {'fpath' : 'val', ...} * - $not Negate operation. * - {'fpath' : {'$not' : val}} //Field not equal to val * - {'fpath' : {'$not' : {'$begin' : prefix}}} //Field not begins with val * - $begin String starts with prefix * - {'fpath' : {'$begin' : prefix}} * - $gt, $gte (>, >=) and $lt, $lte for number types: * - {'fpath' : {'$gt' : number}, ...} * - $bt Between for number types: * - {'fpath' : {'$bt' : [num1, num2]}} * - $in String OR Number OR Array val matches to value in specified array: * - {'fpath' : {'$in' : [val1, val2, val3]}} * - $nin - Not IN * - $strand String tokens OR String array val matches all tokens in specified array: * - {'fpath' : {'$strand' : [val1, val2, val3]}} * - $stror String tokens OR String array val matches any token in specified array: * - {'fpath' : {'$stror' : [val1, val2, val3]}} * - $exists Field existence matching: * - {'fpath' : {'$exists' : true|false}} * - $icase Case insensitive string matching: * - {'fpath' : {'$icase' : 'val1'}} //icase matching * Ignore case matching with '$in' operation: * - {'name' : {'$icase' : {'$in' : ['tHéâtre - театр', 'heLLo WorlD']}}} * For case insensitive matching you can create special index of type: `JBIDXISTR` * - $elemMatch The $elemMatch operator matches more than one component within an array element. * - { array: { $elemMatch: { value1 : 1, value2 : { $gt: 1 } } } } * Restriction: only one $elemMatch allowed in context of one array field. * * - Queries can be used to update records: * $set Field set operation. * - {.., '$set' : {'field1' : val1, 'fieldN' : valN}} * $upsert Atomic upsert. If matching records are found it will be '$set' operation, * otherwise new record will be inserted with fields specified by argment object. * - {.., '$upsert' : {'field1' : val1, 'fieldN' : valN}} * $inc Increment operation. Only number types are supported. * - {.., '$inc' : {'field1' : number, ..., 'field1' : number} * $dropall In-place record removal operation. * - {.., '$dropall' : true} * $addToSet Atomically adds value to the array only if its not in the array already. * If containing array is missing it will be created. * - {.., '$addToSet' : {'fpath' : val1, 'fpathN' : valN, ...}} * $addToSetAll Batch version if $addToSet * - {.., '$addToSetAll' : {'fpath' : [array of values to add], ...}} * $pull Atomically removes all occurrences of value from field, if field is an array. * - {.., '$pull' : {'fpath' : val1, 'fpathN' : valN, ...}} * $pullAll Batch version of $pull * - {.., '$pullAll' : {'fpath' : [array of values to remove], ...}} * * NOTE: Negate operations: $not and $nin not using indexes * so they can be slow in comparison to other matching operations. * * NOTE: Only one index can be used in search query operation. * * QUERY HINTS (specified by `hints` argument): * - $max Maximum number in the result set * - $skip Number of skipped results in the result set * - $orderby Sorting order of query fields. * - $fields Set subset of fetched fields If a field presented in $orderby clause it will be forced to include in resulting records. * Example: * hints: { * "$orderby" : { //ORDER BY field1 ASC, field2 DESC * "field1" : 1, * "field2" : -1 * }, * "$fields" : { //SELECT ONLY {_id, field1, field2} * "field1" : 1, * "field2" : 1 * } * } * * Many query examples can be found in `testejdb/t2.c` test case. * * @param EJDB database handle. * @param qobj Main BSON query object. * @param orqobjs Array of additional OR query objects (joined with OR predicate). * @param orqobjsnum Number of OR query objects. * @param hints BSON object with query hints. * @return On success return query handle. On error returns NULL. */ EJDB_EXPORT EJQ* ejdbcreatequery(EJDB *jb, bson *qobj, bson *orqobjs, int orqobjsnum, bson *hints); ~~~~~~ EJDB C Samples ------------------------------------ You can find some code samples in: * [tcejdb/samples](https://github.com/Softmotions/ejdb/tree/master/tcejdb/samples) * [tcejdb/testejdb](https://github.com/Softmotions/ejdb/tree/master/tcejdb/testejdb) Basic EJDB architecture ------------------------------------ **EJDB database files structure** ~~~~~~ . ├── ├── _ ├── ... ├── _ └── __. ~~~~~~ Where * `````` - name of database. It is metadata DB. * `````` - name of collection. Collection database. * `````` - JSON field path used in index * `````` - Collection index extension: * ```.lex``` String index * ```.dec``` Number index * ```.tok``` Array index Limitations ------------------------------------ * One ejdb database can handle up to 1024 collections. * Indexes for objects in nested arrays currently not supported (#37) TODO ------------------------------------ * Collect collection index statistic Related software ------------------------------------ [Connect session store backed by EJDB database](https://github.com/Softmotions/connect-session-ejdb)