Sqlite喜欢只在第一个字母上工作吗？
问题描述 投票：-1回答：2
我有以下代码来使用Where和And过滤器。
public void Add(Expression<Func<T, object>> memberExpression, object memberValue)
{
if (_Query.ToString() != string.Empty)
_Query.Append(" AND ");
_Query.Append(string.Format(" [{0}] = {1}", NameOf(memberExpression), memberValue == null ? "NULL" : string.Format("'{0}'", memberValue)));
}
我采用了相同的方法并进行了一些更改，以便在sqlite中使用Like，但只有在输入2个字母时不再带来任何值的情况下才能使用输入的第一个字母
代码如：
public void Like(Expression<Func<T, object>> memberExpression, object memberValue)
{
if (_Query.ToString() != string.Empty)
_Query.Append(" AND ");
_Query.Append(string.Format(" [{0}] LIKE '{1}' ", NameOf(memberExpression), memberValue == null ? "NULL" : "%" + memberValue + "%"));
}
随着一封信
超过1个字母看到你应该带上“威廉”
对于那些正在谈论sql注入的人，我只是得到了这个Sqlite示例，我做了一点点。
编辑：
sql在“Db浏览器为Sqlite”
类
using System;
using System.Collections.Generic;
using System.Data.SQLite;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
namespace SQLiteWithCSharp.Utility
{
/// <summary>
/// Author : Swaraj Ketan Santra
/// Email : [email protected]
/// Date : 25/02/2017
/// Description : Entity/model classes as T
/// </summary>
/// <typeparam name="T"> Class and newable type</typeparam>
#region Attributes
/// <summary>
/// Use this attribute to decorate the properties on your model class.
/// Only those properties that are having exactly the same column name of a DB table.
/// </summary>
public class DbColumnAttribute : Attribute
{
/// <summary>
/// Set true if implicit conversion is required.
/// </summary>
public bool Convert { get; set; }
/// <summary>
/// Set true if the property is primary key in the table
/// </summary>
public bool IsPrimary { get; set; }
/// <summary>
/// Denotes if the field is an identity type or not.
/// </summary>
public bool IsIdentity { get; set; }
}
#endregion
#region BaseService
/// <summary>
/// Use with Entity/Model class only
/// </summary>
/// <typeparam name="T"></typeparam>
public abstract class BaseService<T> where T : class, new()
{
#region Constructor
public BaseService()
{
}
/// <summary>
/// Pass the connection string in constructor
/// </summary>
/// <param name="connectionString"></param>
public BaseService(string connectionString)
{
Context.ConnectionString = connectionString;
}
#endregion
#region Public methods
/// <summary>
/// To get SQLite connection object
/// </summary>
/// <returns>SQLiteConnection object</returns>
public SQLiteConnection GetConnection()
{
return new SQLiteConnection(Context.ConnectionString);
}
/// <summary>
/// Inserts the single record into table
/// </summary>
/// <param name="entity"></param>
public long Add(T entity)
{
long identity = 0;
bool hasIdentity = false;
StringBuilder columns = new StringBuilder();
StringBuilder values = new StringBuilder();
IList<PropertyInfo> propertyInfos = GetPropertyInfoList(entity);
foreach (PropertyInfo i in propertyInfos)
{
var ca = i.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (ca != null)
{
if (!ca.IsIdentity)
{
columns.Append(string.Format("[{0}],", i.Name));
values.Append(string.Format("{0},",
i.GetValue(entity) == null ? "NULL" : string.Format("'{0}'", i.GetValue(entity))));
}
else
{
hasIdentity = true;
}
}
}
if (columns.ToString() != string.Empty)
{
columns.Remove(columns.Length - 1, 1); // Remove additional comma(',')
values.Remove(values.Length - 1, 1); // Remove additional comma(',')
StringBuilder qry = new StringBuilder();
qry.Append(string.Format("INSERT INTO [{0}] ( {1} ) VALUES ( {2} ); SELECT last_insert_rowid();"
, entity.GetType().Name, columns, values));
identity = hasIdentity ? Execute(qry.ToString(), true) : Execute(qry.ToString());
}
return identity;
}
/// <summary>
/// Inserts multiple records into a table
/// </summary>
/// <param name="entities"></param>
public void AddRange(IList<T> entities)
{
StringBuilder qry = new StringBuilder();
foreach (T entity in entities)
{
StringBuilder columns = new StringBuilder();
StringBuilder values = new StringBuilder();
IList<PropertyInfo> propertyInfos = GetPropertyInfoList(entity);
foreach (PropertyInfo i in propertyInfos)
{
var ca = i.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (ca != null)
{
if (!ca.IsIdentity)
{
columns.Append(string.Format("[{0}],", i.Name));
values.Append(string.Format("{0},",
i.GetValue(entity) == null ? "NULL" : string.Format("'{0}'", i.GetValue(entity))));
}
}
}
if (columns.ToString() != string.Empty)
{
columns.Remove(columns.Length - 1, 1); // Remove additional comma(',')
values.Remove(values.Length - 1, 1); // Remove additional comma(',')
qry.AppendLine(string.Format("INSERT INTO [{0}] ( {1} ) VALUES ( {2} );"
, entity.GetType().Name, columns, values));
}
}
try
{
Execute(qry.ToString());
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// Updates single entity
/// </summary>
/// <param name="entity"></param>
public void Update(T entity)
{
StringBuilder columns = new StringBuilder();
StringBuilder clause = new StringBuilder();
IList<PropertyInfo> propertyInfos = GetPropertyInfoList(entity);
foreach (PropertyInfo i in propertyInfos)
{
var ca = i.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (ca != null)
{
if (!ca.IsPrimary)
{
columns.Append(string.Format("[{0}] = {1},", i.Name,
i.GetValue(entity) == null ? "NULL" : string.Format("'{0}'", i.GetValue(entity))));
}
else
{
clause.Append(string.Format("[{0}] = '{1}'", i.Name, i.GetValue(entity)));
}
}
}
if (columns.ToString() != string.Empty)
{
columns.Remove(columns.Length - 1, 1);
StringBuilder qry = new StringBuilder();
qry.Append(string.Format("UPDATE [{0}] SET {1} WHERE {2};"
, entity.GetType().Name, columns, clause));
Execute(qry.ToString());
}
}
/// <summary>
/// Updates mutiple entities in single query
/// </summary>
/// <param name="entities"></param>
public void UpdateRange(IList<T> entities)
{
StringBuilder qry = new StringBuilder();
foreach (T entity in entities)
{
StringBuilder columns = new StringBuilder();
StringBuilder clause = new StringBuilder();
#region MyRegion
IList<PropertyInfo> propertyInfos = GetPropertyInfoList(entity);
foreach (PropertyInfo i in propertyInfos)
{
var ca = i.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (ca != null)
{
if (!ca.IsPrimary)
{
columns.Append(string.Format("[{0}] = {1},", i.Name,
i.GetValue(entity) == null ? "NULL" : string.Format("'{0}'", i.GetValue(entity))));
}
else
{
clause.Append(string.Format("[{0}] = '{1}'", i.Name, i.GetValue(entity)));
}
}
}
if (columns.ToString() != string.Empty)
{
columns.Remove(columns.Length - 1, 1);
qry.AppendLine(string.Format("UPDATE [{0}] SET {1} WHERE {2};"
, entity.GetType().Name, columns, clause));
}
#endregion
}
Execute(qry.ToString());
}
/// <summary>
/// Find single item
/// </summary>
/// <param name="cmdText"></param>
public T GetById(object id)
{
T entity = new T();
StringBuilder clause = new StringBuilder();
IList<PropertyInfo> pInfos = GetPropertyInfoList(entity);
foreach (var pi in pInfos)
{
var pk = pi.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (pk != null && pk.IsPrimary)
{
clause.Append(string.Format("[{0}]='{1}'", pi.Name, id));
break;
}
}
if (clause.ToString() != string.Empty)
{
StringBuilder qry = new StringBuilder();
qry.Append(string.Format("SELECT * FROM [{0}] WHERE {1}", entity.GetType().Name, clause));
var _entities = ExecuteGet(qry.ToString());
if (_entities != null && _entities.Count > 0)
entity = _entities[0];
}
return entity;
}
public IList<T> Find(IEnumerable<object> ids)
{
IList<T> entities = new List<T>();
StringBuilder clause = new StringBuilder();
var entity = new T();
IList<PropertyInfo> pInfos = GetPropertyInfoList(entity);
foreach (var pi in pInfos)
{
var pk = pi.GetCustomAttribute(typeof(DbColumnAttribute)) as DbColumnAttribute;
if (pk != null && pk.IsPrimary)
{
string _ids = string.Empty;
foreach (var id in ids)
{
if (_ids != string.Empty)
_ids = _ids + ",";
_ids = _ids + id.ToString();
}
clause.Append(string.Format("[{0}] IN ({1})", pi.Name, _ids));
break;
}
}
if (clause.ToString() != string.Empty)
{
StringBuilder qry = new StringBuilder();
qry.Append(string.Format("SELECT * FROM [{0}] WHERE {1}", entity.GetType().Name, clause));
entities = ExecuteGet(qry.ToString());
}
return entities;
}
public IList<T> Find(IFilter<T> filter)
{
T entity = new T();
return ExecuteGet<T>(filter);
}
/// <summary>
/// Get all records
/// </summary>
/// <param name="cmdText"></param>
public IList<T> GetAll()
{
T entity = new T();
return ExecuteGet(string.Format("SELECT * FROM [{0}]", entity.GetType().Name));
}
/// <summary>
/// Pass comman text to get values
/// </summary>
/// <param name="commandText"></param>
/// <returns></returns>
public IList<T> GetAll(string commandText)
{
return ExecuteGet(commandText);
}
public IList<TEntity> GetAll<TEntity>(string commandText)
where TEntity : class, new()
{
return ExecuteGet<TEntity>(commandText);
}
#endregion
#region Private methods
/// <summary>
/// Execute Only ; No return
/// </summary>
/// <param name="cmdText"></param>
//private void Execute(string cmdText)
//{
// using (var connection = GetConnection())
// {
// connection.Open();
// SQLiteCommand cmd = new SQLiteCommand(cmdText, connection);
// cmd.ExecuteNonQuery();
// }
//}
private long Execute(string cmdText, bool returnIdentity = false)
{
using (var connection = GetConnection())
{
connection.Open();
SQLiteCommand cmd = new SQLiteCommand(cmdText, connection);
if (returnIdentity)
{
return (long)cmd.ExecuteScalar();
}
else
{
cmd.ExecuteNonQuery();
return 0;
}
}
}
/// <summary>
/// Execute and get records. of the native type
/// </summary>
/// <param name="cmdText"></param>
/// <returns></returns>
private IList<T> ExecuteGet(string cmdText)
{
using (var connection = GetConnection())
{
connection.Open();
SQLiteCommand cmd = new SQLiteCommand(cmdText, connection);
using (var reader = cmd.ExecuteReader())
{
return new EntityMapper().Map<T>(reader);
}
}
}
/// <summary>
/// Get list of items by specifying the type
/// </summary>
/// <param name="cmdText"></param>
/// <returns></returns>
private IList<TEntity> ExecuteGet<TEntity>(string cmdText)
where TEntity : class, new()
{
using (var connection = GetConnection())
{
connection.Open();
SQLiteCommand cmd = new SQLiteCommand(cmdText, connection);
using (var reader = cmd.ExecuteReader())
{
return new EntityMapper().Map<TEntity>(reader);
}
}
}
/// <summary>
/// Pass filter to get records in entity format
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="filter"></param>
/// <returns></returns>
private IList<TEntity> ExecuteGet<TEntity>(IFilter<TEntity> filter)
where TEntity : class, new()
{
using (var connection = GetConnection())
{
connection.Open();
SQLiteCommand cmd = new SQLiteCommand(filter.Query, connection);
using (var reader = cmd.ExecuteReader())
{
return new EntityMapper().Map<TEntity>(reader);
}
}
}
/// <summary>
/// Pass SQLite reader to get the specified entity type
/// when you are reading dataset or multiple records
/// </summary>
/// <param name="reader"></param>
/// <returns></returns>
private IList<TEntity> ExecuteGet<TEntity>(SQLiteDataReader reader)
where TEntity : class, new()
{
return new EntityMapper().Map<TEntity>(reader);
}
private IList<PropertyInfo> GetPropertyInfoList(T entity)
{
return entity.GetType().GetProperties()
.Where(p => p.CustomAttributes.FirstOrDefault(x => x.AttributeType == typeof(DbColumnAttribute)) != null).ToList();
}
private IList<PropertyInfo> GetPropertyInfoList<TEntity>(TEntity entity)
{
return entity.GetType().GetProperties()
.Where(p => p.CustomAttributes.FirstOrDefault(x => x.AttributeType == typeof(DbColumnAttribute)) != null).ToList();
}
#endregion
}
#endregion
#region Cache/Storage
public static class Context
{
public static string ConnectionString { get; set; }
}
#endregion
#region Entity Mapper
public class EntityMapper
{
// Complete
public IList<T> Map<T>(SQLiteDataReader reader)
where T : class, new()
{
IList<T> collection = new List<T>();
while (reader.Read())
{
T obj = new T();
foreach (PropertyInfo i in obj.GetType().GetProperties()
.Where(p => p.CustomAttributes.FirstOrDefault(x => x.AttributeType == typeof(DbColumnAttribute)) != null).ToList())
{
try
{
var ca = i.GetCustomAttribute(typeof(DbColumnAttribute));
if (ca != null)
{
if (((DbColumnAttribute)ca).Convert == true)
{
if (reader[i.Name] != DBNull.Value)
i.SetValue(obj, Convert.ChangeType(reader[i.Name], i.PropertyType));
}
else
{
if (reader[i.Name] != DBNull.Value)
i.SetValue(obj, reader[i.Name]);
}
}
}
catch (Exception ex)
{
#if DEBUG
Console.WriteLine(ex.Message);
Console.ReadLine();
#endif
#if !DEBUG
throw ex;
#endif
}
}
collection.Add(obj);
}
return collection;
}
}
#endregion
#region Interfaces
public interface IFilter<T> where T : class, new()
{
string EntityName { get; }
string Query { get; }
void Add(Expression<Func<T, object>> memberExpression, object memberValue);
}
#endregion
#region Filter
public class Filter<T> : IFilter<T> where T : class, new()
{
public Filter()
{
_Query = new StringBuilder();
EntityName = typeof(T).Name;
}
public void Add(Expression<Func<T, object>> memberExpression, object memberValue)
{
if (_Query.ToString() != string.Empty)
_Query.Append(" AND ");
_Query.Append(string.Format(" [{0}] = {1}", NameOf(memberExpression), memberValue == null ? "NULL" : string.Format("'{0}'", memberValue)));
}
public void Like(Expression<Func<T, object>> memberExpression, object memberValue)
{
if (_Query.ToString() != string.Empty)
_Query.Append(" AND ");
_Query.Append(string.Format(" [{0}] LIKE '{1}' ", NameOf(memberExpression), memberValue == null ? "NULL" : "%" + memberValue + "%"));
}
public string EntityName { get; private set; }
private readonly StringBuilder _Query;
/// <summary>
/// Returns SELECT statement with WHERE clause based on the expression passed; This is CommandText
/// </summary>
public string Query
{
get
{
return string.Format("SELECT * FROM [{0}] {1} {2};"
, EntityName
, _Query.ToString() == string.Empty ? string.Empty : "WHERE"
, _Query.ToString());
}
}
private string NameOf(Expression<Func<T, object>> exp)
{
MemberExpression body = exp.Body as MemberExpression;
if (body == null)
{
UnaryExpression ubody = (UnaryExpression)exp.Body;
body = ubody.Operand as MemberExpression;
}
return body.Member.Name;
}
}
#endregion
}
班级员工
using SQLiteWithCSharp.Utility;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace SQLiteWithCSharp.Models
{
public class Employee
{
[DbColumn(IsIdentity =true, IsPrimary =true)]
public long EmployeeId { get; set; }
[DbColumn]
public string Name { get; set; }
[DbColumn]
public string Surname { get; set; }
[DbColumn]
public string Date_Birth { get; set; }
[DbColumn]
public string Home_Address { get; set; }
[DbColumn]
public string City { get; set; }
[DbColumn]
public string Postcode { get; set; }
[DbColumn]
public string Telephone { get; set; }
[DbColumn]
public string Mobile { get; set; }
[DbColumn]
public string Email { get; set; }
}
}
2个回答
2
投票
投票
在0:13和0:14观看您的视频。滚动条部分消失在顶部。表格的顶部隐藏在标题后面。
-1
投票
投票
检查您的Sqlite是否具有区分大小写的LIKE。
PRAGMA case_sensitive_like=ON;
PRAGMA case_sensitive_like=OFF;
我修改了String.Format，如下所示。您不能在引号中包含NULL。所以我也在编写单引号作为替换的一部分。这在sqlite中对我来说很好。
_Query.Append(string.Format(" [{0}] LIKE {1} "
, NameOf(memberExpression)
, memberValue == null ? "NULL" : "'%" + memberValue + "%'"));
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