我有查询:
var query = DataContext.Fotos.Where(x => x.Pesquisa.Contais("myTerm")
生成的SQL是:
选择 ... 来自Fotos AS [Extent1] 在哪里[Extent1]。[Pesquisa]喜欢N'%mytem%'
但我需要使用:
选择 ... 来自Fotos AS [Extent1] 包含([Extent1]。[Pesquisa],'我的用语')
如何使用实体框架6执行全文搜索?
答案 0 :(得分:22)
似乎Entity Framework 6不支持全文搜索,但有拦截器的解决方法。
http://www.entityframework.info/Home/FullTextSearch
更新链接不起作用,所以这是原始内容:
Microsoft TSQL通过谓词支持全文查询 (CONTAINS和FREETEXT)
例如,您有表注释
Create table Notes ( Id int Identity not null, NoteText text ) CREATE FULLTEXT CATALOG [Notes Data]
当您在此表中搜索包含“John”字样的记录时,您就可以了 需要发出
SELECT TOP (10) * from gps.NOTES WHERE contains(NoteText, '(john)')
不幸的是,Enity框架不支持全文搜索 谓词仍然。对于EFv6,您可以使用 拦截。
这个想法是在内部用一些魔术词包装搜索文本 plain String.Contains代码并使用拦截器来解开它 在SqlCommand中执行sql之前。
首先,让我们创建拦截器类:
public class FtsInterceptor : IDbCommandInterceptor { private const string FullTextPrefix = "-FTSPREFIX-"; public static string Fts(string search) { return string.Format("({0}{1})", FullTextPrefix, search); } public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { } public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { } public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext) { RewriteFullTextQuery(command); } public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext) { } public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { RewriteFullTextQuery(command); } public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { } public static void RewriteFullTextQuery(DbCommand cmd) { string text = cmd.CommandText; for (int i = 0; i < cmd.Parameters.Count; i++) { DbParameter parameter = cmd.Parameters[i]; if (parameter.DbType.In(DbType.String, DbType.AnsiString, DbType.StringFixedLength, DbType.AnsiStringFixedLength)) { if (parameter.Value == DBNull.Value) continue; var value = (string)parameter.Value; if (value.IndexOf(FullTextPrefix) >= 0) { parameter.Size = 4096; parameter.DbType = DbType.AnsiStringFixedLength; value = value.Replace(FullTextPrefix, ""); // remove prefix we added n linq query value = value.Substring(1, value.Length - 2); // remove %% escaping by linq translator from string.Contains to sql LIKE parameter.Value = value; cmd.CommandText = Regex.Replace(text, string.Format( @"\[(\w*)\].\[(\w*)\]\s*LIKE\s*@{0}\s?(?:ESCAPE N?'~')",parameter.ParameterName), string.Format(@"contains([$1].[$2], @{0})",parameter.ParameterName)); if (text == cmd.CommandText) throw new Exception("FTS was not replaced on: " + text); text = cmd.CommandText; } } } } }
我使用了扩展功能,可以像这样定义:
static class LanguageExtensions { public static bool In<T>(this T source, params T[] list) { return (list as IList<T>).Contains(source); } }
现在让我们编写一个如何使用它的示例。我们需要实体类注意:
public class Note { public int Id { get; set; } public string NoteText { get; set; } }
映射配置:
public class NoteMap : EntityTypeConfiguration<Note> { public NoteMap() { // Primary Key HasKey(t => t.Id); } }
我们的DbContext祖先:
public class MyContext : DbContext { static MyContext() { DbInterception.Add(new FtsInterceptor()); } public MyContext(string nameOrConnectionString) : base(nameOrConnectionString) { } public DbSet<Note> Notes { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Configurations.Add(new NoteMap()); } }
现在我们准备好使用它了。让我们搜索'john':
class Program { static void Main(string[] args) { var s = FtsInterceptor.Fts("john"); using (var db = new MyContext("CONNSTRING")) { var q = db.Notes.Where(n => n.NoteText.Contains(s)); var result = q.Take(10).ToList(); } } }
答案 1 :(得分:0)
您可以对EF使用原始SQL查询。所以,还有另一个简单的解决方法。
using (DBContext context = new DBContext())
{
string query = string.Format("Select Id, Name, Description From Fotos Where CONTAINS(Pesquisa, '\"{0}\"')", textBoxStrToSearch.Text);
var data = context.Database.SqlQuery<Fotos>(query).ToList();
dataGridView1.DataSource = data;
}
省略输入验证等。 编辑:根据OP的查询修改代码。