Tablestore:Query information about a table

Prerequisites

• An OTSClient instance is initialized. For more information, see Initialize an OTSClient instance.

• A mapping table is created. For more information, see Create mapping tables for tables.

Parameters

Examples

The following sample code provides an example on how to execute the describe test_table statement to query the information about test_table:

func getTableDesc(client *tablestore.TableStoreClient) {
    // Create an SQL request. 
    request := &tablestore.SQLQueryRequest{Query: "describe test_table"}

    // Obtain the response to the SQL request. 
    response, err := client.SQLQuery(request)
    if err != nil {
        panic(err)
    }

    // Obtain the schema of the returned results of the SQL request. 
    columns := response.ResultSet.Columns()
    for l := 0; l< len(columns); l++ {
        fmt.Printf("%v:%v ", columns[l].Name, columns[l].Type.String())
    }

    // Use SQL ResultSet to obtain all returned results of the SQL request. 
    fmt.Println("]\nresponse resultset:")
    resultSet := response.ResultSet
    for resultSet.HasNext() {
        row := resultSet.Next()
        for i := range columns {
            if i > 0 {
                fmt.Printf(", ")
            }
            value, err := row.GetString(i)
            if err != nil {
                panic(err)
            }
            fmt.Printf(value)
        }
        fmt.Println()
    }
}

Sample response:

response table schema: [Field:STRING Type:STRING Null:STRING Key:STRING Default:STRING Extra:STRING]
response resultset:
pk, varchar(1024), NO, PRI, ,
long_value, bigint(20), YES, , ,
double_value, double, YES, , ,
string_value, mediumtext, YES, , ,
bool_value, tinyint(1), YES, , ,

References

• To use a mapping table to query data that meets specific conditions, execute the SELECT statement. For more information, see Query data.

• To update the attribute column of a mapping table after an attribute column of the data table is changed, execute the ALTER TABLE statement. For more information, see Update attribute columns of mapping tables.

• To delete a mapping table, execute the DROP MAPPING TABLE statement. For more information, see Delete mapping tables.