/// <summary> /// Count documents matching a query. This method does not deserialize any document. Needs indexes on query expression /// </summary> public int Count(string predicate, params BsonValue[] args) => this.Count(BsonExpression.Create(predicate, args));
/// <summary> /// Count documents matching a query. This method does not deserialize any documents. Needs indexes on query expression /// </summary> public long LongCount(string predicate, BsonDocument parameters) => this.LongCount(BsonExpression.Create(predicate, parameters));
/// <summary> /// Returns true if query returns any document. This method does not deserialize any document. Needs indexes on query expression /// </summary> public bool Exists(string predicate, BsonDocument parameters) => this.Exists(BsonExpression.Create(predicate, parameters));
/// <summary> /// Returns true if query returns any document. This method does not deserialize any document. Needs indexes on query expression /// </summary> public bool Exists(string predicate, params BsonValue[] args) => this.Exists(BsonExpression.Create(predicate, args));
/// <summary> /// Find all files that match with predicate expression. /// </summary> public IEnumerable <LiteFileInfo <TFileId> > Find(string predicate, params BsonValue[] args) => this.Find(BsonExpression.Create(predicate, args));
/// <summary>
/// [ EXPLAIN ]
/// SELECT {selectExpr}
/// [ INTO {newcollection|$function} [ : {autoId} ] ]
/// [ FROM {collection|$function} ]
/// [ INCLUDE {pathExpr0} [, {pathExprN} ]
/// [ WHERE {filterExpr} ]
/// [ GROUP BY {groupByExpr} ]
/// [ HAVING {filterExpr} ]
/// [ ORDER BY {orderByExpr} [ ASC | DESC ] ]
/// [ LIMIT {number} ]
/// [ OFFSET {number} ]
/// [ FOR UPDATE ]
/// </summary>
private IBsonDataReader ParseSelect()
{
// initialize query definition
var query = new Query();
var token = _tokenizer.ReadToken();
query.ExplainPlan = token.Is("EXPLAIN");
if (query.ExplainPlan)
{
token = _tokenizer.ReadToken();
}
token.Expect("SELECT");
// read required SELECT <expr> and convert into single expression
query.Select = BsonExpression.Create(_tokenizer, BsonExpressionParserMode.SelectDocument, _parameters);
// read FROM|INTO
var from = _tokenizer.ReadToken();
if (from.Type == TokenType.EOF || from.Type == TokenType.SemiColon)
{
// select with no FROM - just run expression (avoid DUAL table, Mr. Oracle)
//TODO: i think will be better add all sql into engine
var result = query.Select.Execute(_collation.Value);
var defaultName = "expr";
return(new BsonDataReader(result.Select(x => x.IsDocument ? x.AsDocument : new BsonDocument {
[defaultName] = x
}), null));
}
else if (from.Is("INTO"))
{
query.Into = ParseCollection(_tokenizer);
query.IntoAutoId = this.ParseWithAutoId();
_tokenizer.ReadToken().Expect("FROM");
}
else
{
from.Expect("FROM");
}
// read FROM <name>
var collection = ParseCollection(_tokenizer);
var ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("INCLUDE"))
{
// read first INCLUDE (before)
_tokenizer.ReadToken();
foreach (var path in this.ParseListOfExpressions())
{
query.Includes.Add(path);
}
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("WHERE"))
{
// read WHERE keyword
_tokenizer.ReadToken();
var where = BsonExpression.Create(_tokenizer, BsonExpressionParserMode.Full, _parameters);
query.Where.Add(where);
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("GROUP"))
{
// read GROUP BY keyword
_tokenizer.ReadToken();
_tokenizer.ReadToken().Expect("BY");
var groupBy = BsonExpression.Create(_tokenizer, BsonExpressionParserMode.Full, _parameters);
query.GroupBy = groupBy;
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("HAVING"))
{
// read HAVING keyword
_tokenizer.ReadToken();
var having = BsonExpression.Create(_tokenizer, BsonExpressionParserMode.Full, _parameters);
query.Having = having;
}
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("ORDER"))
{
// read ORDER BY keyword
_tokenizer.ReadToken();
_tokenizer.ReadToken().Expect("BY");
var orderBy = BsonExpression.Create(_tokenizer, BsonExpressionParserMode.Full, _parameters);
var orderByOrder = Query.Ascending;
var orderByToken = _tokenizer.LookAhead();
if (orderByToken.Is("ASC") || orderByToken.Is("DESC"))
{
orderByOrder = _tokenizer.ReadToken().Is("ASC") ? Query.Ascending : Query.Descending;
}
query.OrderBy = orderBy;
query.Order = orderByOrder;
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("LIMIT"))
{
// read LIMIT keyword
_tokenizer.ReadToken();
var limit = _tokenizer.ReadToken().Expect(TokenType.Int).Value;
query.Limit = Convert.ToInt32(limit);
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("OFFSET"))
{
// read OFFSET keyword
_tokenizer.ReadToken();
var offset = _tokenizer.ReadToken().Expect(TokenType.Int).Value;
query.Offset = Convert.ToInt32(offset);
}
ahead = _tokenizer.LookAhead().Expect(TokenType.Word, TokenType.EOF, TokenType.SemiColon);
if (ahead.Is("FOR"))
{
// read FOR keyword
_tokenizer.ReadToken();
_tokenizer.ReadToken().Expect("UPDATE");
query.ForUpdate = true;
}
// read eof/;
_tokenizer.ReadToken().Expect(TokenType.EOF, TokenType.SemiColon);
return(_engine.Query(collection, query));
}
/// <summary> /// Find all files that match with predicate expression. /// </summary> public IEnumerable <LiteFileInfo <TFileId> > Find(string predicate, BsonDocument parameters) => this.Find(BsonExpression.Create(predicate, parameters));
/// <summary> /// Delete all documents based on predicate expression. Returns how many documents was deleted /// </summary> public int DeleteMany(string predicate, params BsonValue[] args) => this.DeleteMany(BsonExpression.Create(predicate, args));
/// <summary> /// Delete all documents based on predicate expression. Returns how many documents was deleted /// </summary> public int DeleteMany(string predicate, BsonDocument parameters) => this.DeleteMany(BsonExpression.Create(predicate, parameters));
/// <summary>
/// Filters a sequence of documents based on a predicate expression
/// </summary>
public ILiteQueryable <T> Where(string predicate, params BsonValue[] args)
{
_query.Where.Add(BsonExpression.Create(predicate, args));
return(this);
}
/// <summary>
/// Filters a sequence of documents based on a predicate expression
/// </summary>
public ILiteQueryable <T> Where(string predicate, BsonDocument parameters)
{
_query.Where.Add(BsonExpression.Create(predicate, parameters));
return(this);
}
