private SqlExpression InferStringTypeMappingOrApplyDefault(SqlExpression expression, RelationalTypeMapping inferenceSourceTypeMapping)
{
if (expression == null)
{
return(null);
}
if (expression.TypeMapping != null)
{
return(expression);
}
if (expression.Type == typeof(string) && inferenceSourceTypeMapping?.ClrType == typeof(string))
{
return(_sqlExpressionFactory.ApplyTypeMapping(expression, inferenceSourceTypeMapping));
}
return(_sqlExpressionFactory.ApplyDefaultTypeMapping(expression));
}
public virtual SqlExpression Translate(
SqlExpression instance,
MethodInfo method,
IReadOnlyList <SqlExpression> arguments,
IDiagnosticsLogger <DbLoggerCategory.Query> logger)
{
if (method.DeclaringType != typeof(MySqlJsonDbFunctionsExtensions))
{
return(null);
}
var args = arguments
// Skip useless DbFunctions instance
.Skip(1)
// JSON extensions accept object parameters for JSON, since they must be able to handle POCOs, strings or DOM types.
// This means they come wrapped in a convert node, which we need to remove.
// Convert nodes may also come from wrapping JsonTraversalExpressions generated through POCO traversal.
.Select(RemoveConvert)
// CHECK: Either just not doing this at all is fine, or not applying it to JsonQuote and JsonUnquote
// (as already implemented below) is needed. An alternative would be to move the check into the local
// json() function.
//
// If a function is invoked over a JSON traversal expression, that expression may come with
// returnText: true (i.e. operator ->> and not ->). Since the functions below require a json object and
// not text, we transform it.
// .Select(
// a => a is MySqlJsonTraversalExpression traversal &&
// method.Name != nameof(MySqlJsonDbFunctionsExtensions.JsonQuote) &&
// method.Name != nameof(MySqlJsonDbFunctionsExtensions.JsonUnquote)
// ? withReturnsText(traversal, false)
// : a)
.ToArray();
var result = method.Name switch
{
nameof(MySqlJsonDbFunctionsExtensions.AsJson)
=> _sqlExpressionFactory.ApplyTypeMapping(
args[0],
_sqlExpressionFactory.FindMapping(method.ReturnType, "json")),
nameof(MySqlJsonDbFunctionsExtensions.JsonType)
=> _sqlExpressionFactory.NullableFunction(
"JSON_TYPE",
new[] { Json(args[0]) },
typeof(string)),
nameof(MySqlJsonDbFunctionsExtensions.JsonQuote)
=> _sqlExpressionFactory.NullableFunction(
"JSON_QUOTE",
new[] { args[0] },
method.ReturnType),
nameof(MySqlJsonDbFunctionsExtensions.JsonUnquote)
=> _sqlExpressionFactory.NullableFunction(
"JSON_UNQUOTE",
new[] { args[0] },
method.ReturnType),
nameof(MySqlJsonDbFunctionsExtensions.JsonExtract)
=> _sqlExpressionFactory.NullableFunction(
"JSON_EXTRACT",
Array.Empty <SqlExpression>()
.Append(Json(args[0]))
.Concat(DeconstructParamsArray(args[1])),
method.ReturnType,
_sqlExpressionFactory.FindMapping(method.ReturnType, "json"),
false),
nameof(MySqlJsonDbFunctionsExtensions.JsonContains)
=> _sqlExpressionFactory.NullableFunction(
"JSON_CONTAINS",
args.Length >= 3
? new[] { Json(args[0]), args[1], args[2] }
: new[] { Json(args[0]), args[1] },
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPath)
=> _sqlExpressionFactory.NullableFunction(
"JSON_CONTAINS_PATH",
new[] { Json(args[0]), _sqlExpressionFactory.Constant("one"), args[1] },
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPathAny)
=> _sqlExpressionFactory.NullableFunction(
"JSON_CONTAINS_PATH",
Array.Empty <SqlExpression>()
.Append(Json(args[0]))
.Append(_sqlExpressionFactory.Constant("one"))
.Concat(DeconstructParamsArray(args[1])),
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPathAll)
=> _sqlExpressionFactory.NullableFunction(
"JSON_CONTAINS_PATH",
Array.Empty <SqlExpression>()
.Append(Json(args[0]))
.Append(_sqlExpressionFactory.Constant("all"))
.Concat(DeconstructParamsArray(args[1])),
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonSearchAny)
=> _sqlExpressionFactory.IsNotNull(
_sqlExpressionFactory.NullableFunction(
"JSON_SEARCH",
Array.Empty <SqlExpression>()
.Append(Json(args[0]))
.Append(_sqlExpressionFactory.Constant("one"))
.Append(args[1])
.AppendIfTrue(
args.Length >= 3, () => args.Length >= 4
? args[3]
: _sqlExpressionFactory.Constant(null, RelationalTypeMapping.NullMapping))
.AppendIfTrue(args.Length >= 3, () => args[2]),
typeof(bool),
null,
false)), // JSON_SEARCH can return null even if all arguments are not null
_ => null
};
return(result);
SqlExpression Json(SqlExpression e) => _sqlExpressionFactory.ApplyTypeMapping(EnsureJson(e), _sqlExpressionFactory.FindMapping(e.Type, "json"));
private SqlExpression MakeStartsWithEndsWithExpressionImpl(
SqlExpression target,
[NotNull] Func <SqlExpression, SqlExpression> targetTransform,
SqlExpression prefixSuffix,
[NotNull] Func <SqlExpression, SqlExpression> prefixSuffixTransform,
bool startsWith)
{
var stringTypeMapping = ExpressionExtensions.InferTypeMapping(target, prefixSuffix);
target = _sqlExpressionFactory.ApplyTypeMapping(target, stringTypeMapping);
prefixSuffix = _sqlExpressionFactory.ApplyTypeMapping(prefixSuffix, stringTypeMapping);
if (prefixSuffix is SqlConstantExpression constantPrefixSuffixExpression)
{
// The prefix is constant. Aside from null or empty, we escape all special characters (%, _, \)
// in C# and send a simple LIKE.
if (constantPrefixSuffixExpression.Value is string constantPrefixSuffixString)
{
// TRUE (pattern == "")
// something LIKE 'foo%' (pattern != "", StartsWith())
// something LIKE '%foo' (pattern != "", EndsWith())
return(constantPrefixSuffixString == string.Empty
? (SqlExpression)_sqlExpressionFactory.Constant(true)
: _sqlExpressionFactory.Like(
targetTransform(target),
prefixSuffixTransform(
_sqlExpressionFactory.Constant(
(startsWith
? string.Empty
: "%") +
EscapeLikePattern(constantPrefixSuffixString) +
(startsWith
? "%"
: string.Empty)))));
}
// https://github.com/PomeloFoundation/Pomelo.EntityFrameworkCore.MySql/issues/996#issuecomment-607876040
// Can return NULL in .NET 5 after https://github.com/dotnet/efcore/issues/20498 has been fixed.
// `something LIKE NULL` always returns `NULL`. We will return `false`, to indicate, that no match
// could be found, because returning a constant of `NULL` will throw later in EF Core when used as
// a predicate.
// return _sqlExpressionFactory.Constant(null, RelationalTypeMapping.NullMapping);
// This results in NULL anyway, but works around EF Core's inability to handle predicates that are
// constant null values.
return(_sqlExpressionFactory.Like(target, _sqlExpressionFactory.Constant(null, stringTypeMapping)));
}
// TODO: Generally, LEFT & compare is faster than escaping potential pattern characters with REPLACE().
// However, this might not be the case, if the pattern is constant after all (e.g. `LCASE('fo%o')`), in
// which case, `something LIKE CONCAT(REPLACE(REPLACE(LCASE('fo%o'), '%', '\\%'), '_', '\\_'), '%')` should
// be faster than `LEFT(something, CHAR_LENGTH('fo%o')) = LCASE('fo%o')`.
// See https://github.com/PomeloFoundation/Pomelo.EntityFrameworkCore.MySql/issues/996#issuecomment-607733553
// The prefix is non-constant, we use LEFT to extract the substring and compare.
return(_sqlExpressionFactory.Equal(
_sqlExpressionFactory.NullableFunction(
startsWith
? "LEFT"
: "RIGHT",
new[] { targetTransform(target), CharLength(prefixSuffix) },
typeof(string),
stringTypeMapping),
prefixSuffixTransform(prefixSuffix)));
}
public virtual SqlExpression Translate(SqlExpression instance, MethodInfo method, IReadOnlyList <SqlExpression> arguments)
{
if (method.DeclaringType != typeof(MySqlJsonDbFunctionsExtensions))
{
return(null);
}
var args = arguments
// Skip useless DbFunctions instance
.Skip(1)
// JSON extensions accept object parameters for JSON, since they must be able to handle POCOs, strings or DOM types.
// This means they come wrapped in a convert node, which we need to remove.
// Convert nodes may also come from wrapping JsonTraversalExpressions generated through POCO traversal.
.Select(removeConvert)
// If a function is invoked over a JSON traversal expression, that expression may come with
// returnText: true (i.e. operator ->> and not ->). Since the functions below require a json object and
// not text, we transform it.
.Select(a => a is MySqlJsonTraversalExpression traversal ? withReturnsText(traversal, false) : a)
.ToArray();
if (!args.Any(a => a.TypeMapping is MySqlJsonTypeMapping || a is MySqlJsonTraversalExpression))
{
throw new InvalidOperationException("The EF JSON methods require a JSON parameter but none was found.");
}
var result = method.Name switch
{
nameof(MySqlJsonDbFunctionsExtensions.JsonType)
=> _sqlExpressionFactory.Function(
"JSON_TYPE",
new[] { args[0] },
typeof(string)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContains)
=> _sqlExpressionFactory.Function(
"JSON_CONTAINS",
args.Length >= 3
? new[] { json(args[0]), args[1], args[2] }
: new[] { json(args[0]), args[1] },
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPath)
=> _sqlExpressionFactory.Function(
"JSON_CONTAINS_PATH",
new[] { json(args[0]), _sqlExpressionFactory.Constant("one"), args[1] },
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPathAny)
=> _sqlExpressionFactory.Function(
"JSON_CONTAINS_PATH",
Array.Empty <SqlExpression>()
.Append(json(args[0]))
.Append(_sqlExpressionFactory.Constant("one"))
.Concat(deconstructParamsArray(args[1])),
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonContainsPathAll)
=> _sqlExpressionFactory.Function(
"JSON_CONTAINS_PATH",
Array.Empty <SqlExpression>()
.Append(json(args[0]))
.Append(_sqlExpressionFactory.Constant("all"))
.Concat(deconstructParamsArray(args[1])),
typeof(bool)),
nameof(MySqlJsonDbFunctionsExtensions.JsonSearchAny)
=> _sqlExpressionFactory.IsNotNull(
_sqlExpressionFactory.Function(
"JSON_SEARCH",
Array.Empty <SqlExpression>()
.Append(json(args[0]))
.Append(_sqlExpressionFactory.Constant("one"))
.Append(args[1])
.AppendIfTrue(args.Length >= 3, () => args.Length >= 4
? args[3]
: _sqlExpressionFactory.Constant(null, RelationalTypeMapping.NullMapping))
.AppendIfTrue(args.Length >= 3, () => args[2]),
typeof(bool))),
nameof(MySqlJsonDbFunctionsExtensions.JsonSearchAll)
=> _sqlExpressionFactory.IsNotNull(
_sqlExpressionFactory.Function(
"JSON_SEARCH",
Array.Empty <SqlExpression>()
.Append(json(args[0]))
.Append(_sqlExpressionFactory.Constant("all"))
.Append(args[1])
.AppendIfTrue(args.Length >= 3, () => args.Length >= 4
? args[3]
: _sqlExpressionFactory.Constant(null, RelationalTypeMapping.NullMapping))
.AppendIfTrue(args.Length >= 3, () => args[2]),
typeof(bool))) as SqlExpression,
_ => null
};
return(result);
SqlExpression json(SqlExpression e) => _sqlExpressionFactory.ApplyTypeMapping(e, _sqlExpressionFactory.FindMapping(e.Type, "json"));
