DBCHQE

DBCHQE is a query facility that enables you to request system default information from the Teradata Database prior to logging on, thereby allowing you to make changes before starting a session.

The Session Character Set, which is obtained on per session basis, can be obtained only after a session has been logged on.

Parameters

DBCHQE (ReturnCode, ContextArea,DBCHQEP)
Int32	*ReturnCode
Int32	*ContextArea
Int32	*DBCHQEP

where:

The parameter...	Is the...
ReturnCode	four-byte address of an area allocated by the application program for storage of a four-byte signed integer.
ContextArea	four-byte address not used by CLI. It is provided to maintain compatibility with the mainframe.
DBCHQEP	four-byte address of the DBCHQEP structure. Some of this structure needs to be filled in by the application program to request query information. The results of the query will then be sent back to the application in this structure.

DBCHQEP Structure

Fields	Data Type	Description
qepLevel	unsigned char	Unassigned numeric format of the parameter list. The values supported in this field are: 1 - The default character set is returned. The application should specify dbcname in qepTDP while using this option. Applications should use this level for querying any other information. 2 - The character set specified for that particular session is returned. The application should specify the session number in qepConn. 129 - (QEPL10NLVL1) Same as level 1. Additionally, uses new fields defined in DBCHQEP structure to give localized CLI error information. 130 - (QEPL10NLVL2) Same as level 2. Additionally, uses new fields defined in DBCHQEP structure to give localized CLI error information.
qepItem	unsigned char	For valid item codes and their descriptions, see “The qepItem Field” on page 231.
qepTLen	unsigned short	Must be set to the TDPID length and TDPID name (dbcname) used for the query.
qepTDP	long	Must be set to the TDPID length and TDPID name (dbcname) used for the query.
qepRsv1[4]	char	Reserved
qepRALen	unsigned short	Unsigned numeric length of the area in which the result of the query is returned. Supplied by caller.
qepRDLen	unsigned short	Unsigned numeric length of the data returned. CLI writes into this field the length of the data it returned in qepRArea. (Sets to the length of the data returned, up to the size of the area specified by the qepRALen field.)
		Set to the length of the data returned (up to the size of the area as specified by the qepRALen field).
*qepRArea	void	Pointer to the area in which the result of the query is returned.
		The length of this area is set by the application in qepRALen.
qepRsv2	unsigned short	Reserved
qepMLen	unsigned short	Reserved
qepMsg	char	Reserved
qepConn	long	Session number
qepMLid	char[2]	Specify the language to be used for any CLI error message associated with the request. EN for English JA for Japanese
*qepMsgP	char	Pointer to an area into which any error message will be placed. Area is allocated by the application.
qepMsgM	unsigned short	Unsigned numeric length, in bytes, of the area pointed to by QepMsgP.
qepRC	unsigned short	Unsigned numeric CLI return code that occurred while processing the DBCHQEP.
qepRMRC	unsigned short	Unsigned numeric CLI return code for any error that occurred while constructing the message. 1 = overflow 4 = Langid used is not supported. Message is returned in English 2 = CLI is not able to build the message because qepMsgP is not provided by the application. 0 = Built the message successfully. If two errors occur simultaneously then the result returned is a bit-wise ‘or’ of the two return codes. (for example, if langid used is default and overflow occurred while returning the message, the output will be: QEPRC = 2 \| 1 = 3
qepRMLen	unsigned short	Unsigned numeric length, in bytes, of the message returned in the area addressed by QEPMSGP.

The qepItem Field

qepItem must be set to a value indicating the type of request, as follows:

Fields	Value	Description
QEPIIID	1	Not supported
QEPISC	2	Returns the name of the default session character set. The return area must be at least 30 bytes because DBCHQE will return a 30-byte character string containing the default character set. All other requests need only a one-byte response area. Refers to the session whose CLIv2 session number is specified in the qepConn field.
QEPIFTSM	3	Transaction Semantics Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for Teradata transaction semantics. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIFLCS	4	Language Conformance Returns the following values to the area pointed to by qepRArea to indicate what type of SQL is supported: 'Y' - Standard SQL and Teradata SQL are supported. 'N' - Only Teradata SQL is supported. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIFUCR	5	Updatable Cursor Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for updatable cursors. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIFRFI	6	Referential Integrity Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for referential integrity. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIDTSM	7	Returns the default transaction semantics, a one-byte character (A or T), for the identified Teradata server to the area pointed to by qepRArea. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEP64K	8	64K Parcels Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for 64K parcels. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPICL2R	9	Release Identifier Returns the release identifier for the CLI being used. The release identifier is an eleven-character value consisting of the two-character major release identifier, the two-character minor release identifier, and the two-character maintenance release identifier, each separated by periods. The last three characters are often blank, but if they are not, they are a period delimiter followed by the two-character E-tape identifier. Note: The intent of the data is not to deduce CLI functionality, but simply to provide the current CLI release identification.
QEPISPF	10	Parallelism Returns a dimensionless value that indicates the extent of parallel processing used internally by the server as a four-byte unsigned integer to the area pointed by qepRArea. Note: The exact meaning of this factor should be considered an implementation detail internal to the Teradata Database. Its utility to a normal application is limited to comparisons of the parallelism of different servers. Note: QEPIDPF is now considered deprecated.
QEPIDMSS	11	Maximum Parcel Size Returns a four-byte value that indicates the maximum size allowed for a segment supported by the server. Segments are used to subdivide special purpose requests that exceed the maximum parcel size.
QEPITDPR	12	Mainframe Compatibility This query level is for mainframe compatibility only. On workstation-attached clients, this query will result in CLI Error 354 (NOQINFO), "The requested query information is unavailable".
QEPIFSSO	13	Single Sign-On Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for single sign-on. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPISU	14	Authentication Returns the actual Teradata Database username of a user logged in using single sign-on or third-party authentication mechanism (such as LDAP). Refers to the numeric session id indicated by qepConn.
QEPIFUPS	15	Atomic UPSERT Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for Atomic UPSERT. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIAOP	16	Array Operations Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for ARRAY OPERATIONS. The length of qepRArea should be at least 1 byte. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIFMRG	17	MERGE INTO Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for MERGE_INTO. The length of the qepRArea should be at least 1 byte. Refers to the Teradata server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIFLOB	18	LOB Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for LOB support. Refers to the server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPITPR	19	Timing Precision Returns the minimum and maximum values for timing-precision supported by client platform, as two signed, 2-byte fields. The QEPTDP is ignored. The length of the qepRArea should be at least 4 bytes.
QEPIXRS	20	Extended Response Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for extended message response. The length of the qepRArea should be at least 1 byte. Refers to the server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIEPU	21	APH Request Returns one of the following to the area pointed to by qepRArea: 1 - supports APH 0 - does not support APH The length of the qepRArea must be at least 2 bytes. Refers to the server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIUD	23	Utility-data support Refers to the server whose TDP identifier is addressed by the qepTDP field. The length of the qepRArea should be at least 4 bytes. The returned 6 byte value contains: first byte - 'Y' or 'N' for the existing Checkpoint-Interval support of the identified Teradata server. second byte - 'Y' or 'N' for the TASM Utility Workload support of the identified Teradata server. third and forth byte - A two-byte unsigned integer 0 or 1 for FastExport Without Spooling support of the identified Teradata server. fifth and sixth bytes - A two-byte unsigned integer 0 or 1 for Extended Load Usage support of the identified Teradata server.
QEPIASL	24	Aggregate Support List Returns a list of values that indicate support for multiple features. The list consists of 1-byte values equal to those returned by the following query items, in order: QEPIFTSM (Transaction Semantics) QEPIFLCS (Language Conformance) QEPIFUCR (Updatable Cursor) QEPIFRFI (Referential Integrity) QEP64K (64K parcels) QEPIFSSO (Single Sign-On) Note: When connecting to a Teradata Database older than V2R6.0, this field will not contain the correct value unless a session has been established. QEPIFUPS (Atomic UPSERT) QEPIAOP (Array Operations) QEPIFMRG (MERGE INTO) QEPIFLOB (LOB) QEPIXRS (Extended Response) (reserved) QEPIEPU (APH request) QEPIRPO (Cursor Positioning) QEPIUDT (UDT) QEPIESS (Enhanced Statement Status) QEPIAPH (APH response) QEPIRCA (Relaxed Call Argument) QEPISIS (Statement Info parcel) QEPIIDE (Large Integer/Decimal) QEPIRID (Insert returns data when identity columns are involved)
QEPIASL (continued)		QEPIDRS (ResultSet) QEPIQBS (QUERY_BAND) QEPIMIU (MERGE INTO) QEPILEU (LOGGING ERRORS) QEPIPD (Default Connection) QEPITSS (Trusted Sessions) QEPILNS (LOB Name) QEPICCS (Column Correlation) QEPITOU (UDT TransformsOff support) QEPISSU (ESS Level support) The length of the qepRArea should be at least 29 bytes. A length of 64 bytes is recommended. Refers to the server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIRPO	25	Cursor Positioning Returns 'N' or 'Y' to the area pointed to by qepRArea to indicate support for cursor positioning. The length of the qepRArea should be at least 1 byte. Refers to the server whose TDP identifier is addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIENC	26	Data Encryption Returns 'N' or 'Y' to indicate whether encryption is both supported and enabled on the database server to which the session is connected. Refers to the session whose CLIv2 session number is specified in the qepConn field.
QEPIRMR	27	CLI Information Returns the CLIv2 release identifier and any customization information for the message table used for the session whose CLIv2 connection number is specified in the qepConn field and the request whose CLIv2 request number is specified in the QEPRQST field. The length of the returned information is up to 48 ASCII characters, consisting of one or two identifiers separated by a comma.
QEPIACS	28	Character Sets Returns the names of the character sets available on the server specified by the TDP identifier addressed by the qepTidp field and has length specified by the qepTlen field. The length of the response is four fixed fields followed by a variable number of character set names. Returns as many whole character set names as will fit into the response area whose length is indicated by qepRalen. If all names are not returned, one of the following queries (that specify the returned token) can be issued to indicate the processing of additional names: qeracsTk - A 4-byte token to be placed into qepToken to retrieve any additional character set names. The content of the token is undefined and must not be altered by the application. qeracsNR - A 2-byte unsigned integer that indicates the number of character set names not returned. qeracsNP - A 2-byte unsigned integer that indicates the number of character set names returned. qeracsLn - A 2-byte unsigned integer that indicates the length of each character set name.
QEPIESS	29	Enhanced Statement Status Returns 'Y' or 'N' to indicate support for enhanced statements. The length of the qepRArea should be at least 1 byte. Refers to the TDP identifier addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIUDT	30	UDT Returns 'Y' or 'N' to indicate support for user-defined types.
QEPIAPH	31	APH Response Returns to the area pointed to by qepRArea a numeric value or 0 to indicate support for APH responses. Refers to the TDP identifier addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIALM	32	Mechanisms Returns a list of supported mechanism names: qeralmTk - A 4-byte token to be placed into QEPTOKEN to retrieve any additional mechanism names. The content of the token is undefined and must not be altered by the application. qeralmNR - A 2-byte unsigned integer that indicates the number of mechanism names not returned. qeralmNP - A 2-byte unsigned integer that indicates the number of mechanism names returned. qeralmLn - A 2-byte unsigned integer that indicates the length of each mechanism name and associated flags.
QEPIDCS	33	Default Character Set Returns the default character set of the database as 30 single-byte characters in the platform character set (ASCII), left-justified, and padded with blanks. The caller of DBCHQE must supply a return area with a length of at least 30 bytes. Note: This field is not returned as a string, so the caller will need to insert a null terminator in the first blank location prior to attempting to write the field to output through print.
QEPIDBR	34	Teradata Database Information Returns the Teradata Database release and version information in two contiguous fields using slightly different formats: 30 single-byte characters in the platform character set (ASCII), left-justified, and padded with blanks, for example, V2R.06.01c.00.00. Immediately following, 32 single-byte characters in the platform character set (ASCII), left-justified, and padded with blanks, for example, 06.01c.00.00. The caller of DBCHQE must supply a return area with a length of at least 62 bytes. Note: Neither field is returned as a string, so the caller will need to insert a null terminator in the first blank location prior to attempting to write the field to output through print. Note: The intent of the data is not to deduce Teradata Database functionality, but simply to provide the release and version information for whatever diagnostic use they may be. The values should not be parsed for any reason since their format is subject to change.
QEPIC2L	35	CLI Limits Returns limits for the Teradata Database affecting an application's values for CLIv2 settings. The response consists of four fields totalling 32 bytes. The caller of DBCHQE (QEPIC2L) must supply a return area of at least 32 bytes. A structure mapping (struct QEPCLLIMIT_) is supplied in dbchqep.h for the convenience of users.
QEPISQL	36	SQL Limits Returns limits for the Teradata Database affecting an application's use of SQL statements. The response consists of 27 fields totalling 20 bytes. The caller of DBCHQE (QEPISQL) must supply a return area of at least 104 bytes. A structure mapping (struct QEPDBLIMIT_) is supplied in dbchqep.h for the convenience of users.
QEPIRCA	37	Relaxed Call Argument Returns an indicator which can be used to determine whether the target server supports the Relaxed Call Argument feature. DBCHQE will return 'Y' if server supports this feature and 'N' if it does not (using ASCII characters). The caller of DBCHQE must supply a return area with a length of at least one byte.
QEPISIS	38	StatementInformation Parcels Returns 'Y' or 'N' to indicate support of StatementInformation parcels.
QEPIIDE	39	Large Integer/Decimal Returns 'Y' or 'N' to indicate support for the Large Integer/Decimal feature. A returned value of 'Y' indicates that the server supports this feature. A returned value of 'N' or any non-zero return code indicates that the server does not support this feature. Returned values are in ASCII. QEPIIDE requires a return area of at least one byte and a target TDPid. This query item is also included in the aggregate support list.
QEPIRID	40	Defines whether data may be returned in response to an SQL Insert operation when Identity columns are involved. A returned value of 'Y' indicates that the server supports this feature. A returned value of 'N' or any non-zero return code indicates that the server does not support this feature. Returned values are in ASCII. QEPIRID requires a return area of at least one byte and a target TDPid. This query item is also included in the aggregate support list.
QEPIDRS	41	ResultSet Returns 'Y' or 'N' to indicate whether stored procedures may return the results of their SQL statements to the application.
QEPIQBS	42	Query Band Returns 'Y' or 'N' to indicate support for the SQL SET QUERY_BAND statement.
QEPIMIU	43	MERGE INTO Returns 'Y' or 'N' to indicate support for the SQL MERGE INTO statement.
QEPILEU	44	Logging Errors Returns 'Y' or 'N' to indicate support for the Teradata SQL LOGGING ERRORS clause.
QEPIPD	45	Default Connection Returns 'Y' or 'N' to indicate support for the Default Connection feature. The caller must supply a return area with a length of at least one byte.
QEPISCS	46	Session Character Set Returns the name of the session character set. The return area must be at least 30 bytes because DBCHQE returns a 30-byte character string that contains the character set. Refers to the session whose CLIv2 session number is specified in the qepConn field.
QEPICCS	47	Column Correlation Returns 'Y' or 'N' to indicate support for the Column Correlation feature.
QEPIUS	48	Utility Session Returns the following values: byte 0-1: Any 2-byte integer – The unformatted Teradata Database node-id associated with the session. 0 – The node-id is not available. byte 2-7: Reserved byte 8-15: 8-byte UInt64 (average actual send throughput in bytes/sec) byte 16-23: 8-byte UInt64 (average actual receive throughput in bytes/sec) byte 24-31: 8-byte UInt64 (average effective send throughput in bytes/sec) byte 32-39: 8-byte UInt64 (average effective receive throughput in bytes/sec) An actual throughput is calculated as data/transmission time. An effective throughput is calculated as data/session time. Refers to the session whose CLIv2 session is specified in the qepConn field. Utility-session is used by proprietary Teradata utilities, and is not intended for other applications.
QEPIDAP	49	Returns the database access path A database access path is a variable-length string that contains the fully qualified domain name and its associated IP address and port number. The following possibilities are equally valid as the prefix for a logon string. Accordingly, the query result consists of one variable-length value. The port number (server side) is always returned following the machine name, FQDN, or IP address, separated by the conventional colon: If a dbcname is used (for example, a machine name sans domain), a dbcname is returned. If a fully-qualified domain name (FQDN) is used, an FQDN returned. If an IP address was used, an IP address will be returned.
QEPITSS	50	Trusted Decisions Returns 'Y' or 'N' to indicate support for the Trusted Decisions feature.
QEPILNS	51	LOB-Name-support Determines whether a DEFERRED LOB can be identified by name. Returns whether the BY NAME phrase is permitted in the USING row descriptor in the request string. Returns 'Y' or 'N' to indicate support for the LOB‑Name‑support feature
QEPITOU	52	UDT-TransformsOff-support The caller of DBCHQE (QEPITOU) must supply a return area of at least two bytes and a target TDPid. The returned value containing one of the following values: 0 - the value of 0 indicates that no UDTs can be transformed. 1 - the value of 1 indicates that UDTs can be transferred in the untransformed mode. 2 - the value of 2 indicates that Period data type can be transformed. DBS will accept from the client either PERIOD Struct metadata and data values, or non-Struct PERIOD metadata and data values.
QEPITRS	53	Trusted-request-support Defines whether the database supports trusted sessions enhancement for the trusted-request option. A returned value of 'Y' indicates that the server supports this feature. A returned value of 'N' or any non-zero return code indicates that the server does not support this feature. The caller of DBCHQE (QEPITRS) must supply a return area of one byte and a target TDPid. This query item is not included in the aggregate support list.
QEPIBI	54	Build-information Returns a list of six values that indicate support for multiple features. The list consists of 1-byte values equal to those returned by the following query items, in order: columnInfo StatementInfo Not Used (reserved) arrayTransformsOff xmlResponseFormat tasmFastFailReq A returned value of 'Y' indicates that the server supports this feature. A returned value of 'N' or any non-zero return code indicates that the server does not support this feature. The caller of DBCHQE(QEPIBI) must supply a return area of at least six bytes. Refers to the session whose CLIv2 session number is specified in the qepConn field.
QEPISES	55	Statement-Independence-support Defines whether DBS supports Statement Independence feature. A returned value of 'Y' indicates that the server supports this feature. A returned value of 'N' or any non-zero return code indicates that the server does not support this feature. The caller of DBCHQE (QEPISES) must supply a return area of one byte and a target TDPid. This query item is not included in the aggregate support list.
QEPISSU	56	Enhanced Statement Status level support Returns a byte indicating ESS level support. The length of the qepRArea should be at least 1 byte. Refers to the TDP identifier addressed by the qepTDP field and has length specified by the qepTLen field.
QEPIILB	57	SLOB support The length of the response is six bytes as follows: First byte - 'Y' or 'N' for LOB support Second byte - 'Y' or 'N' for LOB Name support Third and fourth bytes - A two-byte unsigned integer 1 or 0 for SLOB Client-to-Server support Fifth and sixth bytes - A two-byte unsigned integer 1 or 0 for SLOB Server-to-Client support

CLIv2-limits

An application can use CLIv2-limits to choose CLIv2 settings to optimize its execution for the accessed Teradata Database, or to prevent errors caused by exceeding limits. Return limits for the Teradata Database affect an application's values for CLIv2 settings. The response consists of four fields totalling 32 bytes.

Item Code	Mnemonic	DBQERC2L (DbqerC2L for C)
Item Code	Mnemonic	Fields	Value
35	QEPIC2L	MaxRequestBytes	An eight-byte unsigned integer.
		MaxSegRequestBytes	An eight-byte unsigned integer.
		MaxUsingDataBytes	An eight-byte unsigned integer.
		MaxResponseBytes	An eight-byte unsigned integer.

Note: The caller of DBCHQE (QEPIC2L) must supply a return area of at least 32 bytes. A structure mapping (struct QEPCLLIMIT_) is supplied in dbchqep.h for the convenience of users.

SQL-limits

An application can use SQL-limits to construct SQL statements to optimize its execution for the accessed Teradata Database, or to prevent errors caused by exceeding limits.

Return limits for the Teradata Database affect an application's use of SQL statements. The response consists of 27 fields totalling 20 bytes.

Item Code	Mnemonic	DBQERSQL (DbqerSQL for C)
Item Code	Mnemonic	Fields	Value
36	QEPISQL	MaxRowBytes	An eight-byte unsigned integer.
		MaxLobBytes	An eight-byte unsigned integer.
		MaxObjectNameChars	A four-byte unsigned integer.
		MaxColinTbl	A four-byte unsigned integer.
		MaxTblinSel	A four-byte unsigned integer.
		MaxColinSel	A four-byte unsigned integer.
		MaxColGrpBy	A four-byte unsigned integer.
		MaxColOrdrBy	A four-byte unsigned integer.
		MaxCharLiteralChars	A four-byte unsigned integer.
		MaxBinLiteralChars	A four-byte unsigned integer.
		MaxColBytes	A four-byte unsigned integer.
		MaxCharChars	A four-byte unsigned integer.
		MaxVarcharChars	A four-byte unsigned integer.
		MaxGraphicChars	A four-byte unsigned integer.
		MaxVargraphicChars	A four-byte unsigned integer.
		MaxByteBytes	A four-byte unsigned integer.
		MaxVarbyteBytes	A four-byte unsigned integer.
		MaxDecimal	A four-byte unsigned integer.
		MaxTimeScale	A four-byte unsigned integer.
		MaxTimeStampScale	A four-byte unsigned integer.
		MaxIntervalToSecondScale	A four-byte unsigned integer.
		MaxFldsUsingRow	A four-byte unsigned integer.
		MaxParamsInRequest	A four-byte unsigned integer.
		MaxSPParams	A four-byte unsigned integer.
		MaxDeferredByNameFileSpec	A four-byte unsigned integer.
		Reserved;	A four-byte unsigned integer.
		MaxJSONBytes;	An eight-byte unsigned integer.

Note: The caller of DBCHQE (QEPISQL) must supply a return area of at least 120 bytes.A structure mapping (struct QEPDBLIMIT_) is supplied in dbchqep.h for the convenience of users.