我在Oracle 11g中有21个表,我需要使用JOIN
子句显示它们。但查询速度太慢引发System.OutOfMemoryException
C#如何获取Oracle数据库中的所有数据
我当前的代码:
try
{
//string ConString;
using (OracleConnection con = new OracleConnection(ConString))
{
//string query = "SELECT PAX.CREATION_DATE,PAX.PNR,PAX.PAX_NMBR,PAX.UPDATE_LEVEL_MOD,PAX.PAX_NAME,PAX.CHANGE_OR_CANCEL_IND,PAX_SEATS.LEG_NMBR,PAX_SEATS.INSTANCE_NMBR,pax_seats.ssr_cd,pax_seats.carrier_cd,pax_seats.seat_nmbr,pax_seats.previous_status_codes FROM PAX INNER JOIN PAX_SEATS ON PAX.PNR = PAX_SEATS.PNR";
string query1 = "SELECT PNR FROM HISTORY_LEGS";
string query2 = "SELECT PAX.CREATION_DATE,PAX.PNR,PAX.PAX_NMBR,PAX.UPDATE_LEVEL_MOD,PAX.PAX_NAME,PAX.CHANGE_OR_CANCEL_IND,PAX_SEATS.LEG_NMBR,PAX_SEATS.INSTANCE_NMBR,pax_seats.ssr_cd,pax_seats.carrier_cd,pax_seats.seat_nmbr,pax_seats.previous_status_codes,PAX_SSRS.SSR_NMBR,PAX_TKT.TKTNMBR,PAX_TKT.ISSUING_AIRLINE, PAX_TKT.ISSUING_OFFC_NMBR, PAX_TKT.ISSUING_COUNTER_CD, PAX_TKT.ISSUING_AGNT_NMBR, PAX_TKT.TKT_IND, PAX_TKT.TKT_STATUS, PAX_TKT.TARIFICATION_IND,PAX_TKT.S_IND,PAX_TKT.ISSUANCE_DATE FROM PAX INNER JOIN PAX_SEATS ON PAX.PNR = PAX_SEATS.PNR RIGHT JOIN PAX_SSRS ON PAX.PNR = PAX_SSRS.PNR RIGHT JOIN PAX_TKT ON PAX.PNR = PAX_TKT.PNR";
//string query4 = "SELECT * FROM PAX";
//string query3 = "SELECT PAX.PAX_NMBR,PAX.PAX_NAME,RES_LEGS.ARNK_IND,RES_LEGS.CARRIER_CD1,RES_LEGS.CARRIER_CD2,RES_LEGS.FLT_NMBR,RES_LEGS.CLASS_CD,RES_LEGS.DAY_OF_WEEK,RES_LEGS.FLT_DATE,RES_LEGS.LEG_ORIGIN_CD,RES_LEGS.LEG_DES_CD,RES_LEGS.CURRENT_STATUS_CD,RES_LEGS.NUMBER_IN_PARTY,RES_LEGS.DP_TIME,RES_LEGS.AR_TIME,RES_LEGS.DATE_CHANGE_IND,RES_LEGS.FLT_IRREGULARITY_IND,RES_LEGS.LEG_TXT,RES_LEGS.PREVIOUS_STATUS_CODES,RES_LEGS.MESSAGE FROM RES_LEGS INNER JOIN PAX ON RES_LEGS.PNR = PAX.PNR";
OracleCommand cmd = new OracleCommand(query2, con);
OracleDataAdapter oda = new OracleDataAdapter(cmd);
DataSet ds = new DataSet();
oda.Fill(ds);
//dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.EnableResizing;
//dataGridView1.RowHeadersVisible = false;
if (ds.Tables.Count > 0)
{
dataGridView1.DataSource = ds.Tables[0].DefaultView;
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
问题:
- 如何获得的所有数据?
- 如何防止System.OutofMemory?
- 如何加快查询执行的性能?
您希望从数据库中返回多少行? – LordBaconPants
每张桌子大约有150,000行。更多数据将被添加 – Sambuu
为什么你需要一次获得所有数据? – mason