public static string ToString(this SqlLockType lockType, bool humanReadable)
{
if (!humanReadable)
{
return(lockType.ToString());
}
if (lockType == SqlLockType.Empty)
{
return("No Lock");
}
var result = new StringBuilder();
if (lockType.Supports(SqlLockType.Shared))
{
result.Append("Shared");
}
if (lockType.Supports(SqlLockType.Update))
{
result.Append("Update");
}
if (lockType.Supports(SqlLockType.Exclusive))
{
result.Append("Exclusive");
}
if (lockType.Supports(SqlLockType.SkipLocked))
{
result.Append("|Skip locked rows");
}
if (lockType.Supports(SqlLockType.ThrowIfLocked))
{
result.Append("|Throw exception if locked");
}
return(result.ToString());
}
/// <inheritdoc/>
public override string Translate(SqlLockType lockType)
{
if (lockType.Supports(SqlLockType.Shared) || lockType.Supports(SqlLockType.SkipLocked))
{
return(base.Translate(lockType));
}
return("WITH LOCK");
}
public override string Translate(SqlLockType lockType)
{
return(lockType.Supports(SqlLockType.SkipLocked) ||
lockType.Supports(SqlLockType.Shared) ||
lockType.Supports(SqlLockType.ThrowIfLocked)
? base.Translate(lockType)
: "FOR UPDATE");
}
public override string Translate(SqlLockType lockType)
{
if (lockType.Supports(SqlLockType.SkipLocked))
{
return(base.Translate(lockType));
}
return(string.Format("FOR {0}{1}",
lockType.Supports(SqlLockType.Shared) ? "SHARE" : "UPDATE",
lockType.Supports(SqlLockType.ThrowIfLocked) ? " NOWAIT" : ""));
}
/// <inheritdoc/>
public override string Translate(SqlLockType lockType)
{
if (lockType.Supports(SqlLockType.Shared))
{
return("LOCK IN SHARE MODE");
}
if (lockType.Supports(SqlLockType.SkipLocked) || lockType.Supports(SqlLockType.ThrowIfLocked))
{
return(base.Translate(lockType));
}
return("FOR UPDATE");
}
/// <summary>
/// 将数据库中的指定表的集合加上读写锁
/// </summary>
/// <param name="tableName">要加锁的表的名字的集合</param>
/// <param name="lockType">要对表加的锁的类型</param>
private void LockTable(IEnumerable <string> tableNames, SqlLockType lockType)
{
string sql = "lock table ";
string lockTypeStr = lockType == SqlLockType.write ? "write" : "read";
foreach (string tableName in tableNames)
{
sql += string.Format(" {0} {1},", tableName, lockTypeStr);
}
sql = sql.TrimEnd(',');
sql += ";";
MySqlCommand cmd = new MySqlCommand(sql, conn);
cmd.ExecuteNonQuery();
}
/// <inheritdoc/>
public override string Translate(SqlLockType lockType)
{
if (lockType.Supports(SqlLockType.Shared))
{
return("SHARED");
}
if (lockType.Supports(SqlLockType.Exclusive))
{
return("EXCLUSIVE");
}
if (lockType.Supports(SqlLockType.SkipLocked) || lockType.Supports(SqlLockType.ThrowIfLocked))
{
return(base.Translate(lockType));
}
return("PENDING"); //http://www.sqlite.org/lockingv3.html Not sure whether this is the best alternative.
}
public override string Translate(SqlLockType lockType)
{
var items = new List <string>();
items.Add("ROWLOCK");
if (lockType.Supports(SqlLockType.Update))
{
items.Add("UPDLOCK");
}
else if (lockType.Supports(SqlLockType.Exclusive))
{
items.Add("XLOCK");
}
if (lockType.Supports(SqlLockType.ThrowIfLocked))
{
items.Add("NOWAIT");
}
else if (lockType.Supports(SqlLockType.SkipLocked))
{
items.Add("READPAST");
}
return(items.ToCommaDelimitedString());
}
public static bool Supports(this SqlLockType available, SqlLockType required)
{
return((available & required) == required);
}
