public virtual IEnumerable <string> DropIdentityForColumn(string columnName, string tableName)
{
var triggerName = CreateTriggerName(columnName, tableName);
using (var writer = FbMigrationSqlGenerator.SqlWriter())
{
writer.WriteLine("EXECUTE BLOCK");
writer.WriteLine("AS");
writer.WriteLine("BEGIN");
writer.Indent++;
writer.Write("if (exists(select 1 from rdb$triggers where rdb$trigger_name = '");
writer.Write(triggerName);
writer.Write("')) then");
writer.WriteLine();
writer.WriteLine("begin");
writer.Indent++;
writer.Write("execute statement 'drop trigger ");
writer.Write(FbMigrationSqlGenerator.Quote(triggerName));
writer.Write("';");
writer.WriteLine();
writer.Indent--;
writer.WriteLine("end");
writer.Indent--;
writer.Write("END");
yield return(writer.ToString());
}
}
public virtual IEnumerable <string> CreateIdentityForColumn(string columnName, string tableName)
{
var identitySequenceName = CreateIdentitySequenceName(columnName, tableName);
using (var writer = FbMigrationSqlGenerator.SqlWriter())
{
writer.WriteLine("EXECUTE BLOCK");
writer.WriteLine("AS");
writer.WriteLine("BEGIN");
writer.Indent++;
writer.Write("if (not exists(select 1 from rdb$generators where rdb$generator_name = '");
writer.Write(identitySequenceName);
writer.Write("')) then");
writer.WriteLine();
writer.WriteLine("begin");
writer.Indent++;
writer.Write("execute statement 'create sequence ");
writer.Write(identitySequenceName);
writer.Write("';");
writer.WriteLine();
writer.Indent--;
writer.WriteLine("end");
writer.Indent--;
writer.Write("END");
yield return(writer.ToString());
}
using (var writer = FbMigrationSqlGenerator.SqlWriter())
{
writer.Write("CREATE OR ALTER TRIGGER ");
writer.Write(FbMigrationSqlGenerator.Quote(CreateTriggerName(columnName, tableName)));
writer.Write(" ACTIVE BEFORE INSERT ON ");
writer.Write(FbMigrationSqlGenerator.Quote(tableName));
writer.WriteLine();
writer.WriteLine("AS");
writer.WriteLine("BEGIN");
writer.Indent++;
writer.Write("if (new.");
writer.Write(FbMigrationSqlGenerator.Quote(columnName));
writer.Write(" is null) then");
writer.WriteLine();
writer.WriteLine("begin");
writer.Indent++;
writer.Write("new.");
writer.Write(FbMigrationSqlGenerator.Quote(columnName));
writer.Write(" = next value for ");
writer.Write(identitySequenceName);
writer.Write(";");
writer.WriteLine();
writer.Indent--;
writer.WriteLine("end");
writer.Indent--;
writer.Write("END");
yield return(writer.ToString());
}
}
