/// <summary>
/// Creates an instance of a database of type <see cref="RelationalDbStorage"/>.
/// </summary>
/// <param name="invariantName">The invariant name of the connector for this database.</param>
/// <param name="connectionString">The connection string this database should use for database operations.</param>
public RelationalDbStorage(string invariantName, string connectionString)
{
ConnectionString = connectionString;
InvariantName = invariantName;
SupportsCommandCancellation = DbConstantsStore.SupportsCommandCancellation(InvariantName);
IsSynchronousAdoNetImplementation = DbConstantsStore.IsSynchronousAdoNetImplementation(InvariantName);
_databaseCommandInterceptor = DbConstantsStore.GetDatabaseCommandInterceptor(InvariantName);
}
/// <summary>
/// Executes a multi-record insert query clause with <em>SELECT UNION ALL</em>.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="storage">The storage to use.</param>
/// <param name="tableName">The table name to against which to execute the query.</param>
/// <param name="parameters">The parameters to insert.</param>
/// <param name="cancellationToken">The cancellation token. Defaults to <see cref="CancellationToken.None"/>.</param>
/// <param name="nameMap">If provided, maps property names from <typeparamref name="T"/> to ones provided in the map.</param>
/// <param name="onlyOnceColumns">If given, SQL parameter values for the given <typeparamref name="T"/> property types are generated only once. Effective only when <paramref name="useSqlParams"/> is <em>TRUE</em>.</param>
/// <param name="useSqlParams"><em>TRUE</em> if the query should be in parameterized form. <em>FALSE</em> otherwise.</param>
/// <returns>The rows affected.</returns>
public static Task <int> ExecuteMultipleInsertIntoAsync <T>(
this IRelationalDbStorage storage,
string tableName,
IEnumerable <T> parameters,
CancellationToken cancellationToken = default,
IReadOnlyDictionary <string, string> nameMap = null,
IEnumerable <string> onlyOnceColumns = null,
bool useSqlParams = true)
{
if (string.IsNullOrWhiteSpace(tableName))
{
throw new ArgumentException("The name must be a legal SQL table name", nameof(tableName));
}
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
var storageConstants = DbConstantsStore.GetDbConstants(storage.InvariantName);
var startEscapeIndicator = storageConstants.StartEscapeIndicator;
var endEscapeIndicator = storageConstants.EndEscapeIndicator;
//SqlParameters map is needed in case the query needs to be parameterized in order to avoid two
//reflection passes as first a query needs to be constructed and after that when a database
//command object has been created, parameters need to be provided to them.
var sqlParameters = new Dictionary <string, object>();
const string insertIntoValuesTemplate = "INSERT INTO {0} ({1}) SELECT {2};";
var columns = string.Empty;
var values = new List <string>();
if (parameters.Any())
{
//Type and property information are the same for all of the objects.
//The following assumes the property names will be retrieved in the same
//order as is the index iteration done.
var onlyOnceRow = new List <string>();
var properties = parameters.First().GetType().GetProperties();
columns = string.Join(",", nameMap == null
? properties.Select(pn =>
$"{startEscapeIndicator}{pn.Name}{endEscapeIndicator}")
: properties.Select(pn =>
$"{startEscapeIndicator}{(nameMap.ContainsKey(pn.Name) ? nameMap[pn.Name] : pn.Name)}{endEscapeIndicator}"));
if (onlyOnceColumns != null && onlyOnceColumns.Any())
{
var onlyOnceProperties = properties.Where(pn => onlyOnceColumns.Contains(pn.Name)).Select(pn => pn).ToArray();
var onlyOnceData = parameters.First();
foreach (var t in onlyOnceProperties)
{
var currentProperty = t;
var parameterValue = currentProperty.GetValue(onlyOnceData, null);
if (useSqlParams)
{
var parameterName = $"@{(nameMap.ContainsKey(t.Name) ? nameMap[t.Name] : t.Name)}";
onlyOnceRow.Add(parameterName);
sqlParameters.Add(parameterName, parameterValue);
}
else
{
onlyOnceRow.Add(string.Format(AdoNetFormatProvider, "{0}", parameterValue));
}
}
}
var dataRows = new List <string>();
var multiProperties = onlyOnceColumns == null ? properties : properties.Where(pn => !onlyOnceColumns.Contains(pn.Name)).Select(pn => pn).ToArray();
var parameterCount = 0;
foreach (var row in parameters)
{
foreach (var currentProperty in multiProperties)
{
var parameterValue = currentProperty.GetValue(row, null);
if (useSqlParams)
{
var parameterName = string.Format(IndexedParameterTemplate, parameterCount);
dataRows.Add(parameterName);
sqlParameters.Add(parameterName, parameterValue);
++parameterCount;
}
else
{
dataRows.Add(string.Format(AdoNetFormatProvider, "{0}", parameterValue));
}
}
values.Add($"{string.Join(",", onlyOnceRow.Concat(dataRows))}");
dataRows.Clear();
}
}
var query = string.Format(insertIntoValuesTemplate, tableName, columns, string.Join(storageConstants.UnionAllSelectTemplate, values));
return(storage.ExecuteAsync(query, command =>
{
if (!useSqlParams)
{
return;
}
foreach (var sp in sqlParameters)
{
var p = command.CreateParameter();
p.ParameterName = sp.Key;
p.Value = sp.Value ?? DBNull.Value;
p.Direction = ParameterDirection.Input;
command.Parameters.Add(p);
}
}, cancellationToken));
}
